


:/v''^,'^^'.§ 



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COPYRIGHT DEPOSm 



AfiRICULTORAL ENTOMOLOGY 



FOR STUDENTS, FARMERS, FRUIT-GROWERS 
AND GARDENERS 



BY 

HERBERT OSBORN, B.Sc, M.Sc. 

PROFESSOR OF ZOOLOGY AND ENTOMOLOGY IN THE OHIO STATE UNIVERSITY, 

COLUMBUS, OHIO, AND DIRECTOR OF THE LAKE LABORATORY, 

CEDAR POINT, OHIO. 



ILLUSTRATED WITH 252 ENGRAVINGS AND A COLORED PLATE 




LEA & FEBIGER 

PHILADELPHIA AND NEW YORK 
1916 



.0^ 



Entered according to the Act of Congress, in the year 1916, by 

LEA & FEBIGER, 
in the Office of the Librarian of Congress. All rights reserved. 



APR 25 1916 

kl,A428C96 



PREFACE 



This book is designed to meet the needs of students and 
others who wish to learn something of insect life especially 
in relation to farm crops and livestock. The author assumes 
that the students who read it will have had some training 
in general biology and will have the guidance of teachers 
familiar with the subject in connection with adequate labor- 
atory facilities and opportunities for field studies. The 
details of laboratory and field studies have not been included 
since these are easily supplied by the teacher. For those 
making individual studies there are many available books 
covering the technic of entomological work. A glossary 
has been included which covers the subject as presented in 
these pages and in most of the reports and bulletins that are 
likely to be consulted by the average student. 

In order to make the scope of the book adequate it has 
been necessary to condense the matter to the most essential 
details, and to omit much that has value but which is not 
absolutely indispensable to the presentation of the important 
principles that concern the practice of economic entomology. 

The author acknowledges his indebtedness to many 
sources of information which are too numerous to mention 
individually, but he is especially indebted to Dr. Howard, 
of the Bureau of Entomology, for the privilege of using the 
illustrations secured from his office and for suggestions; to 



iv PREFACE 

Professors Washburn and Bruner for the loan of plates; 
to the Iowa Experiment Station for use of figures, and the 
Ohio Experiment Station for a number of photographs for 
original use here. Professors Hine, INIetcalf, Barrows, 
Mr. Kostir and Mr. Drake have assisted in reading manu- 
script and proof and have generously given the author 
the use of photographs and drawings. 

H. O. 
Columbus, Ohio, 1916. 



CONTENTS. 



CHAPTER I. 
Introduction 17 

CHAPTER II. 

Class Arachnida 22 

CHAPTER III. 

The Six-footed Insects 38 

CHAPTER IV. 
Lower Pterygota 51 

CHAPTER V. 
Order Hemiptera 93 

CHAPTER VI. 
Neuroptera and Allies 165 

CHAPTER VII. 
Coleoptera. Beetles . 172 

CHAPTER VIII. 

Lepidoptera 206 

CHAPTER IX. 
Order Diptera 248 

CHAPTER X. 
Bees and Wasps 291 

CHAPTER XI. 

Principles of Economic Entomology 312 

Glossary 329 

Index •. . 339 



AGMCULTUML ENTOMOLOGY 



CHAPTER I. 
INTRODUCTION. 

The recent rapid growth in the subject of Agricultural 
Entomology makes it a difficult matter to bring together 
a comprehensive statement that will cover all of its different 
phases in a thorough manner. Some idea of its growth 
may be indicated by the fact that instead of a single ento- 
mologist employed in the United States Department of 
Agriculture, as was the case forty years ago, there are now 
several hundred who are devoting their entire time to the 
investigation of entomological problems, practically all of 
which are related to agriculture. 

A similar development of this work has taken place in 
the State Experiment Stations, and there are also State 
Entomological departments working in almost every State, 
and in many of them two or three different organizations, 
each with a large quota of workers. 

Economic entomology in its wider sense covers all those 
phases of the subject which have to do with insects of 
importance in relation to mankind. The forms which 
have distinctly agricultural relation are so numerous and 
represent so completely all the different groups of insects 
that we are compelled to include a very general survey of 
the subject. 

Some idea of the size of the group of insects and of its 
place in biological study may be secured from the statement 
2 ^ (17) 



18 INTRODUCTION 

that there are now known and have been scientifically recog- 
nized and described something over three hundred thousand 
species of insects, a number which far surpasses that of all 
other groups of animals together. Furthermore, the immense 
numbers of individuals in each species and the great facility 
which they possess for migration and rapidity of increase 
make them a very dominant group of animals. 

Not all insects, to be sure, have a direct importance to 
mankind, but there is so large a number that are very 
directly related to human interests in the way of destruction 
of property or menace to health that it is unnecessary to 
emphasize their importance. Many estimates have been 
attempted of the extent of loss of crops, livestock, forests, 
agricultural products, etc., and while none of these can be 
considered exact, it is increasingly evident that such estimates 
are conservative and in many cases the loss is greater than 
is recognized. One of the current estimates is that about 
10 per cent, of the aggregate of farm crops in the United 
States is lost by insect attack, and if this be taken as an 
approximate proportion there is something like one billion 
dollars to be counted an economic loss from this source 
each year. 

It must be admitted that the entomologist has not been 
able as yet to solve all of the problems of insect control. 
There will doubtless be many cases where a practical control 
of insects may not be reached for many years, but for a 
considerable number of the most common and serious pests 
it has been possible to discover methods by which a very 
large proportion of the loss can be prevented. One phase 
of entomological work, therefore, is the demonstration of 
these possibilities in order to secure a general adoption of 
control measures that have been proved successful. 

While it is manifestly impossible to include in a small 
book any full discussion of the many phases of entomology, 
it is the purpose of this work to present a basis for the under- 
standing of field observations, and especially for the under- 
standing of the many articles relating to economic insects 
which are now appearing in Government and State pub- 



INTRODUCTION 19 

lications. Many of these publications are available and will 
be found to contain an immense store of information, much 
of it of very practical value, but its greatest utility will be 
found to rest upon some acquaintance with the general 
facts of insect life and insect habits. These are so dependent 
upon certain conditions of structure ajid development that 
acquaintance with some of the fundamental biological 
features of insect life are essential to the most effective 
utilization. 

Formerly all of the arthropods, that is, all animals with 
jointed bodies and jointed appendages, were grouped under 
the head of insects, and even yet this term has a pretty 
wide application in popular usage, although it is seldom 
used now to cover as wide a range as formerly. The Arth- 
ropods, as a whole, include crustaceans, myriapods, arach- 
nids, hexapods, or six-footed insects, and of these the air- 
breathing forms, all except the crustaceans, are still quite 
commonly treated as insects. 

The Onychophora is a tropical group including peripatus, 
the most primitive of tracheate animals, and would on this 
basis be considered as falling next to the Crustacea. 

The most generalized next to these, the myriapods, might 
be counted as possessing the greater number of insect-like 
characters. This group, however, does not include any 
forms that possess wings, but in the matter of antennae and 
the tracheal respiration they are closely associated with 
insects. The members of this group are, for the most part, 
of comparatively little economic importance. A few of the 
species included in the group of centipedes (Ckilopoda) are 
poisonous, and in tropical countries are of some importance 
on this account. The few species that occur in temperate 
regions have little importance except as they may feed upon 
other insects which occur under the litter at the surface of 
the ground. 

One species, the house centipede, a peculiar long-legged 
creature, w^hich is occasionally found in cellars or around 
houses, usually where there is some dampness, is, however, 
of a certain amount of importance because of its feeding 



2U 



INTRODUCTION 



111)011 insects, and is looked ii})on as rather servieeahle in the 
destruction of flies. It is a quite ungainly looking creature, 




Fig. 1. — Scutigera forceps: Adult — natural size. (From Marlatt, 
Div. Ent., U, S. Dept. Ag.) 



with slender, flattened body, extremely long legs, and an 
apparent duplication of anterior and posterior ends. 
The millipedes (Diplopoda) are nearly cylindrical in 



INTRODUCTION 21 

shape, are recognized as having two pairs of legs to each 
apparent segment and there is usually a large number of 
segments, 40 to 100 or more, so that the name thousand- 



" 




^^"--■-. 


! / 








\ 


'• V ■ 






\^ 


y^ 


' ^ -■* ." 








/ 







Fig. 2. — Scutigera forceps: a, newly hatched individual; 6, one of the 
legs of same; c, terminal segment of body showing undeveloped legs coiled 
up within — all enlarged. (After Marlatt. Div. Ent., U, S. Dept. Ag.) 

legged worm is fairly descriptive. Most of these species 
are found in moist places and feed upon vegetable debris, 
but a few have been recorded as attacking vegetation, and 
one species has been credited with injuring seed corn. 



CHAPTER II. 
CLASS ARACHNIDA. 

In the strict technical sense the group Arachnida may be 
excluded from the Insecta, but in general usage, and to a 
large extent in entomological practice, these divisions are 
put together, and it seems desirable that the group should 
be given a place in any work dealing with the insects in 
general. 

The group Arachnida includes spiders, scorpions, harvest- 
men, mites, ticks, etc., and is characterized by the presence 
of four pairs of legs, the absence of antennae and compound 
eyes, and the lack of distinct metamorphosis, although 
in certain groups there is a considerable change from the 
newly hatched or six-legged form to the mature eight-legged 
stage. 

In general structure the Arachnida agree with other 
Arthropoda, but the head and thorax are usually merged 
into a cephalothorax separated from the abdomen by a 
more or less distinct stalk; in the Acarina, however, this 
separation is not marked and the body is without distinct 
separation of head, thorax, and abdomen. 

The economic importance of the group depends upon 
their attacks upon certain crops, from the fact that many 
of the species, such as spiders and harvestmen, are uniformly 
predaceous and serve as important checks upon injurious 
species; while other forms, such as the mites and ticks, are 
parasitic upon domestic animals and man, and some of the 
species occupy a most important relationship as carriers 
of infectious diseases. 

The subdivisions of the group are, for the most part, very 
well marked and represent ancient groups which have 
diverged quite widely from each other. 

The scorpions (Scorpionida), mostly tropical in distribu- 
(22) 



CLASS ARACHNIDA 23 

tion, are represented by fossils in early geological times, 
and are noted as possessing poison glands. They are recog- 
nized by the broad cephalothorax, a division of the abdomen 
into two portions, an anterior preabdomen of seven seg- 
ments, and a slender hinder postabdomen of six segments, 
on the last one of which there is a large poison gland and 
sting. The sting is distinctly venomous and fatal to insects 
or smaller animals, but seldom serious in its effect on the 
human species. 

The Pseudoscorpionida are minute forms resembling 
scorpions in the width of the body and the long pedipalps, 
but have no postabdomen or sting. They occur somewhat 
commonly under bark or decaying logs or occasionally in old 
papers or books, where they may secure book lice as food. 

The Pedipalpi, or whip scorpions, have a tropical or 
subtropical distribution and differ from the preceding groups 
in the presence of a long, slender bristle or whip extending 
from the hinder abdominal segment. 

In the group Solpugida there is an exceptional separation 
of head and thorax and the abdomen is distinctly segmented, 
while the chelicerse are greatly enlarged and strongly chelate. 
These are not only largely tropical, but are particularly 
characteristic of arid regions. One species occurs in the 
Rocky Mountain region as far north as Colorado. They 
are carnivorous in habit, but not of particular economic 
importance, as they occur usually in small numbers and in 
locations which do not offer opportunity to capture espe- 
cially injurious insects. 

The Phalangida, or harvestmen, often called "daddy- 
longlegs," are somewhat large and resemble spiders in 
appearance, but the abdomen is not distinctly separated 
from the thorax and the legs are in most species extremely 
long. They feed on insects, especially on flies and other 
small forms, and are to be counted as distinctly beneficial. 
On account of a strong pungent odor they are disagreeable 
to handle, but their presence in gardens and other places 
where insects abound may be considered as distinctly desir- 
able. 



24 



CLASS ARACHNIDA 



Order ARANEIDA. 

This jijroii]) includes tlie familiar s])i(lers which are very 
generally distributed over tlie world, and occupy a rather 
conspicuous place among other animals. Their body is 
sharply divided into cei)hal()th()rax and abdomen, and the 
four pairs of legs are usually nearly equal in length. The 




Fig. .3. — Epeira scolopetaria, showdng normal position of spider in web 
head downward. A vibrator at x agitating the web will cause the spider 
to rush at once to point of contact. (Photo by Prof. W, M. Barrows.) 



eyes are simple and usually eight in number, and the large 
mandibles are attached at right angles to the axis of the 
body. In some species these are provided with a poison 
duct. The })ite is venomous to smaller organisms, and in 
some of the larger, like the tarantula, the bite is a serious 
matter for man. Spiders oft'er a great many attractive 



ORDER ACARINA 



25 



features, particularly in their web-making habit and in their 
adaptation for the capture of prey. They are distinctly 
carnivorous in habit and may be considered useful, since 
the majority of them capture insects, and the kinds of 
insects captured are quite generally such as are detrimental 
to man. In general, therefore, spiders should be left unmo- 
lested and their insect-feeding habits utilized in the reduc- 
tion of injurious insects. 





Fig. 4. — The common red spider (Tetranychus bimaculatus) : a, adult; 
b, palpus; c, claws; a, greatly enlarged; h, c, still more enlarged. (After 
Banks. From Bur. Ent., U. S. Dept. Ag.) 



Order ACARINA. 

These are commonly known as mites, ticks, scab insects, 
mange insects, etc., and are in general distinguished by 
having no prominent separation between the different 
regions of the body, the head, thorax, and abdomen, forming 
one closely connected structure. They have eight legs, 
except in the early stages, when there are but six; the 
eyes are often small or obsolete, the spiracles reduced to 
one pair, sometimes apparently wanting; the mouth parts 



26 



CLASS ARACHNIDA 



are fitted for piercing, biting, or in some cases for combined 
biting and suction, there being usually a pair of slender, 
sharp mandibles capable of penetrating the skin of the 
host animals. Much variation of habit exists, and ranges 
from free forms to strictly parasitic forms. 




Fig. 5 — Tetranychus gloveri: Adult — much enlarged. (Titus, Div. 
Ent., U. S. Dept. Ag.) 



Harvest Mites; Chiggers. 

In the family TromhidiidoB, which includes normally plant- 
feeding species, we find a few species which have adopted 
a phase of parasitism which, though apparently abnormal, 
results in extreme annoyance to the animals affected. 

Apparently the most abundant species in this country 
is the Leptus irritans of Riley, which is illustrated herewith. 
This occurs in a large portion of the United States, and 
occasions during the summer months an enormous amount 
of suffering. It ranges north in the Mississippi Valley into 



ORDER ACARINA 27 

central Iowa, at least, and in Ohio to Lake Erie, appearing 
by the latter part of June or fore part of July, but becoming 
especially annoying during August. In the latitude of 
Washington it is very abundant early in June, and farther 
south its season extends until, in southern Mexico, what 
is apparently the same species is abundant and equally 
annoying in January. 

The form in which this pest is observed usually is the 
larval or six-legged form. It is nearly circular in outline, 
the legs extending well beyond the margins of the body, 
of a bright red color, and so minute that it is only with 
the closest scrutiny that it can be detected. 



Fig. 6. — Leptus irritans to the right and americana to the left. (From 

Riley.) 

It is brushed from the leaves of various plants on to the 
hands or clothing of people and to the bodies of other animals, 
and the mite then proceeds to burrow into the skin, not- 
withstanding the fact that, so far as all evidence shows, 
this proceeding is absolutely fatal to it and prevents any 
possibility of its maturing or producing eggs. 

There is great difference in the susceptibility shown by 
different persons to the attacks of this mite, some not 
seeming to be affected seriously by them, while others must 
submit to extreme torture every time they happen to become 
attacked by them, even if but few in number. 



28 CLASS ARACHNIDA 

As the mites are invariably secured })y working among 
raspberries, currants, or other sln-ub})ery wliicli luirbors 
them, or by walkin^^ in grass or low herbage wliere they 
occur, sometimes even by sitting or lying for a short time 
upon grass or clover, it is evident that the best precaution 
for suscej^tible ])ersons is to avoid all such ex])osure. When 
such avoidance is impracticable, the clothing may be made 
to fit closely at the wrists and ankles, and then as soon as 
possible after having been exposed to the mites make an 
entire change of clothing, bathe in hot, soapy water, and 
if any indications of mites are present, wash the affected ])arts 
with diluted carbolic acid, 1 part to 50 or 100 parts water. 

In the tropics rum or w^hisky is recommended as a wash, 
and diluted alcohol can be used with good results. 

With a little pains it is possible to locate the mites, as 
they may be found before they have completely buried 
themselves in the skin in the centre of the little red swelling 
that has been raised by their preliminary irritation, and if 
they are removed at this stage, instead of being allowed to 
bury themselves in the skin the subsequent inflammation 
and itching will be largely prevented. 

Family Gamasidse. — The family Gamasidce contains a 
large number of small mites, most of them being free or 
semiparasitic in habit. 

A large number occur as parasites on various species of 
insects, but the two species to be mentioned here occur on 
birds, and are sometimes very troublesome. 

The Bird Tick (Dermanyssiis avium). — The bird tick is a 
very familiar form to keepers of cage birds, and is known in 
many places as the red mite. It occurs on a great variety 
of birds, and has sometimes been considered to embrace 
the chicken tick, mention of which follows, but that is 
now generally conceded to represent a distinct form. The 
mites are easily seen with the naked eye and appear as 
animated red specks running over the bodies of birds, or 
on the perches, bars of cages, etc. The eggs are laid in 
cracks or corners of the cage, where may be found also the 
molted skins and often numerous young and old mites. 



ORDER ACARINA 



29 



The attacks on the birds are made probably for the 
most part at night, but the mites are usually well filled 
with blood, which gives them their red color. 

The use of perches that are solid, smooth, and free from 
cracks, and the frequent dipping of these in hot water, and 
the thorough cleansing of the entire cage, using boiling water 
if there are inaccessible cracks, will serve to destroy the 
pests. 




Fig. 7. — Poultry tick (Dermanyssus gallince): a, adult; 6, tarsus; c, 
mouth parts; d and e, young — all enlarged. (After Osborn, Bur. Ent., U. 
S. Dept. Ag.) 



The Poultry Tick {Dermanyssus (jalUfKp). ^One of the 
most persistent and injurious of the pests of the hennery 
is the little chicken mite, which gathers on the fowls, espe- 
cially at night, and sucks their blood. It is a well-known 
form, and has been described for many years, though in 
many works it is confused with the preceding species or 
considered simply a variety of that form. Its distribution 
seems to extend pretty generally over the world where 
domestic fowls are kept. 



30 CLASS ARACHNIDA 

The full-grown mites are about 1 mm. long, of a light 
gray or wliitish color, with dark patches showing through 
the skin, but when full fed have a distinct red color. They 
swarm in cracks and corners of the henhouse, and often 
when numerous, over all surrounding objects, and at such 
time are liable to become a great pest to man and such other 
animals as they may get access to. 

The dust bath is considered of use in checking this pest, 
but when there is a general infestation, the best plan will 
be found to clear the house, then spray well with kerosene 
or kerosene emulsion, taking pains to reach the cracks; 
thoroughly drench the roosts with hot water or kerosene, 
benzine, or gasoline, whitewash the house, or dust with 
carbolated lime, and then daub the ends of the roosts, where 
they come in contact with supports, with coal tar, so the 
mites w^ould have to cross it to reach the fowls. 

Family Ixodidae. — This family includes forms known 
commonly as ticks, and familiar examples are the dog tick 
or wood tick, frequently found upon domestic animals, 
and other examples are the cattle tick of the Southern States 
and spotted fever tick of the Rocky Mountain region. In 
this group the body is robust and becomes much distended 
in the female when the eggs are developed. The mouth 
parts are adapted for puncturing the skin of host animals, 
and the species generally attach themselves to warm-blooded 
animals as 'a part of the life-cycle, and in some cases this 
attachment is permanent, while in others it is temporary 
and the individual tick may occupy several different hosts 
in the course of its life-cycle. 

The family is of particular importance because of the 
fact that some of the species are carriers of important 
diseases, most notable of which is Texas fever, transmitted 
by the cattle tick. The spotted fever tick is the carrier of 
spotted fever. 

The Pigeon Tick {Argas reflexus). — The pigeon tick is a 
common species on pigeons found mainly in pigeon houses, 
and sucks the blood of pigeons for its nutriment. It is, 
however, able to survive for long periods without food, 



ORDER ACARINA 



31 



some recorded instances are of individuals kept in confine- 
ment for two years without food, but which moulted at 
frequent intervals. 

The related Argas persicus occurs both in the old world 
and America. It is a troublesome pest for chickens and is 
credited also with attacks on human beings. 




Fig. 8. 



-Argas miniatus, a tick which infests poultry. Greatly enlarged. 
(Banks, Div. Ent., U. S. Dept. Ag.) 



The Cattle Tick (Margaropus annulatus). — The cattle tick, 
as already mentioned, has received probably more atten- 
tion than any other species, as it has been known for many 
years as the carrier of Texas fever in cattle, and its great 
importance to the cattle industry has been the occasion 
for elaborate studies regarding its habits. In this species 
the newly hatched tick locates as soon as possible upon 
a warm-blooded animal, preferably upon cattle, as these 
seem to be by all means the preferred host. Once located 
they retain their attachment until mature. The females 
when mature and gorged with eggs loosen their hold, drop 
to the ground and eggs may be distributed wherever the 
adults fall. The period of incubation differs greatly, with 
regard to temperature, so that the rate of development and 
number of generations differ much at different seasons of 



32 CLASS ARACHNIDA 

the year. An important fact concerning tlie transfer of 
disease is that tlie protozoa in the diseased animal are taken 
into the l)ody of the tick, and within tlie body of this host 
may enter the eggs, so that young ticks that have never fed 
upon an animal may serve to introduce the parasite in an 
individual that has not previously had the disease. 

Elimination of ticks from the cattle and prevention of 
their attacks therefore become essential factors in the 
eradication of Texas fever. To accomplish the eradica- 
tion of the ticks in any given locality it is necessary to 
rotate animals from one field to another, allowing time for 
hatching of eggs and dying of the ticks before the field again 
is used as a pasture for cattle. Working upon this basis, 
considerable areas in the Southern States are now con- 
sidered tick-free and the hope is that the quarantine line 
will be pushed farther and farther south until ultimately 
the ticks and associated disease may be completely eradi- 
cated. Certain districts in Tennessee and North Carolina 
are now considered tick-free and released from quarantine 
restrictions. 

The Spotted Fever Tick {Dermacentor wnvsta). — The 
spotted fever tick has come into great prominence in recent 
years because of the determination that it serves as the 
carrier of the much-dreaded spotted fever. This disease 
has caused many deaths in Montana and adjacent States, 
and the rate of mortality for individuals attacked is very 
high, so that its appearance is very much dreaded. 

It has been shown that this disease is carried by this 
particular species of tick, and in no other way. It differs 
in habit from the cattle tick in that a number of different 
hosts may be fed upon at different periods in its develop- 
ment. Usually the young larvae attach themselves to ground 
squirrels or smaller mammals and remain upon these from 
three to five days, after which they drop to the ground. 
After a resting period of from one to three weeks the skin 
is moulted and an eight-legged form appears, which in turn 
attaches itself to some host and feeds for several days, 
dropping to the ground and developing into the adult 



OIWFlR ACARINA 



33 





&r%< 



Fig. 9 



Fig. 10 





Fig. 11 



Fig. 12 




Fig. 13 , Fig. 14 

Figs. 9 to 14. — The spotted fever tick {Dermacentor venustus and Derma- 
centor albipictus). (Hunter and Bishopp.) 
Fig. 9, adult spotted fever tick which has deposited eggs. Fig. 10, larva 
of spotted fever tick. Fig. 11, engorged nymph of spotted fever tick. 
Fig. 12, the same, ventral view. Fig. 13, adult male of Dermacentor albi- 
pictus. Fig. 14, adult female of Dermacentor albipictus, unengorged. 
3 



34 



CLASS ARACHNIDA 



stage. In the adult stage still another host is sought, this 
time usually some of the larger animals, such as domestic 
cattle or sheep, and })robably in the wild condition such 




Fig. lo.—Psoroptes communis, var. equi. (Reduced from Furstenberg, 
after Murray.) 



animals as the antelope or Rocky Mountain sheep or other 
ruminants of the Rocky Mountain region. On these hosts 
fertilization occurs and the females then drop to the ground 



ORDER ACARINA 35 

where the eggs are laid and a new cycle begun. The disease 
has some remarkable limitations in its distribution which 
are probably associated with the distribution of the ticks or 
the animals which serve as a reserve for the disease germs. 

Family Sarcoptidse. — This family includes parasitic mites, 
affecting particularly birds and mammals. 

The Sheep Scab Mite {Psoroptes communis, var. oms). — 
The sheep scab mite produces a very serious condition 
among sheep, evidenced by matting and tagging of wool 
and the formation of thick, encrusting scabs. The eggs of 
this mite are minute, glistening white specks, longer than 
broad and nearly uniform in thickness. They may be 
found under the scabs by careful inspection, and their 
detection, even when mites are not seen, may be taken as 
evidence of the disease. 

The larvse have nearly the same shape as the adults, but 
are to be distinguished by the fact that only six legs are 
apparent. 

The full-grown mites are nearly as broad as long, and are 
characterized by their piercing mouth parts and the struc- 
ture of the two posterior pairs of legs (see Fig. 15). In the 
male the fourth is much reduced, and the third bears a 
long thread-like appendage passing the sucker, while in 
the female this leg carries two long, thread-like organs and 
no sucker. 

The only treatment for this species worthy of recognition 
is that of dipping, and this, if properly done, will secure the 
extermination of the pest. A flock once freed will not 
become again infested except by exposure to infected animals 
or by the introduction of scabby individuals. 

So important is this parasite deemed that many of the 
States have adopted stringent laws for the quarantine of 
infected animals and for prescribing dips that must be used. 

The particular kind of dip is of less importance than the 
thorough use of the one selected. The tobacco dips, sulphur 
and lime dips, and also several of the patent dips prepared 
by reputable firms can be recommended. The main objec- 
tion to the latter, perhaps, is the fact that the user must 



36 



CLASS A RA CIINI DA 



pay a rather ex()r})itant ])ri(*e for a few simple ehemicals, 
and further, in ease of the arsenieal dips, that lie ma\- not 
know the ingredients or their proportions and thereby endan- 
uer the animals treated. 

The Itch Mite. — The iteh mite, or " iteh inseet," affecting 
man is perhaps becoming a rather rare pest in civilized 
communities, but since it occurs at times on domestic 
animals, and in certain varieties becomes at times a serious 
pest to sucli animals, it deserves mention here. Authors 




Fig. 16. — Sarcoptes ficabiei: male and female. 
Furstenberg, after Murray.) 



(Reduced from 



have differed greatly in their treatment of the species, some 
making a different species for each host animal, believing 
that they could find distinctive characters in the size, 
arrangement of spines, etc.; but recent authors have com- 
bined most of these under the one species, scabiei, though in 
some cases retaining the varietal distinction for various 
hosts. 
All stages of the parasite occur on the host upon which 



ORDER ACARINA 37 

it is absolutely dependent for existence. Generation after 
generation may occur on the same animal. The mite 
burrows under th^ skin, in this respect differing from scab 
mites. 

The adult mites are flattened, rather circular in outline, 
and may be separated from related forms by the character 
of the feet and by the presence of six short spines or thorns 
on the thoracic portion and fourteen on the abdominal 
portion of the body. 

Eggs are deposited along the burrow as the mite extends 
its channel into the deeper portions of the skin, and as they 
hatch the young feed upon the surrounding tissues, and it 
is said moult four times before maturity. When fully grown 
they wander around and mate on the surface of the skin, 
after which the females begin a fresh burrow. 

Infection with this parasite is accompanied by intense 
itching during the formation of pustules and inflamed areas, 
and while in man it is usually confined to the base of the 
fingers and between the knuckles, in aggravated cases the 
whole hand and arm may become invaded. 

The "seven-year itch," "army itch," and "Jackson itch" 
are simply aggravated cases, where from lack of good sani- 
tation the mites are able to thrive better than usual. 

In the human subject the application of sulphur ointment, 
in addition to frequent washing with soap and hot water, 
and for domestic animals the use of washes and dips, as for 
scab mites, are to be adopted. 



CHAPTER III. 
THE SIX-FOOTED INSECTS. 

The Ilexapoda, or the true insects, inchide those forms 
with three pairs of legs, and the group is further distin- 
guished from the other tracheate forms by large compound 
eyes and for a considerable portion of the group the presence 
of one or two pairs of wings. 

Of the various arthropods this division includes by far 
the greater number of species and to a large extent those 
forms which have the greatest agricultural importance. 

STRUCTURE OF INSECTS. 

There are some details in the structure of insects that 
have a special importance in connection with the use of 
remedies and some that from their frequent use in the 
description of injurious species require explanation as a 
basis for proper understanding of these principles. These 
will be treated here as briefly as may be, bearing in mind 
constantly this main issue in their presentation. 

The insect body is divided into three regions, head, thorax, 
and abdomen. The first appears to be one solid segment, 
though believed fundamentally to consist of six or seven 
segments closely fused together. The thorax has three 
segments usually pretty closely joined, while the abdomen 
possesses from three to nine visible segments, and these 
articulate so as to be free to move on each other. 

The head bears appendages, a number of definite struc- 
tures connected w^ith sensation or nutrition, and which are 
of special service in separating the different groups of insects. 
The antennse are jointed appendages usually situated on 
the upper and front part of the head, composed of a varying 
(38) 



STRUCTURE OF INSECTS 



39 



number of segments and modified in a great variety of ways 
in different groups of insects. Some of these modifications 
may be mentioned briefly. 

The joints may be widened so as to appear toothed along 
one margin, in which case they are called serrate. If con- 
stricted at each end so as to appear like a string of beads 
they are called moniliform; if expanded widely toward the 
apex on one side they form a series of comb-like teeth and 
are then said to be pectinate; if swollen toward the apex, 
or club-shaped, they are called clavate; and if this swollen 
portion is confined to a few of the terminal segments and 
expanded so as to form a ball they are capitate. In moths 




Spiracles 
Abdomen 



Prothorax Head 



Fig. 17. — Anatomy of grasshopper. (Reduced from Packard.) 



they may be provided with a series of plume-like expansions 
on either side and are then bipectinate, or if extremel}^ wide 
and feathery are called plumose. 

The compound eyes are usually large and conspicuous, 
and composed of an immense number of facets, these num- 
bering in some insects many thousands, being especially 
numerous in dragon flies, horse flies, and some butter- 
flies. The ocelli are the more simple eyes, composed of a 
single lens, and are often so minute as to be seen with diffi- 
culty except by the aid of a lens. They may be three in 
number, sometimes two and in some cases wanting. Usually 
they are located between the compound eyes, and on either 



40 THE SIX-FOOTED IXSECTS 

side a sliort distance from tlie marjj^iii of tlie comiK)!!!!!! eye, 
and the tliird, if ])resent, lower down on the face and on the 
middle line. 

The lower ])orti()n of the face is divided into cJypeus, 
which forms the basis for attachment of the lahrum or upper 
lip, the movable flajvlike part which covers the front part 
of the mouth. Beneath this are the strong mandibles 
capable of cutting and tearing the leaves of plants, and in 
some cases of inflicting a severe bite if handled. 

Next to these is a pair of more slender appendages, the 
auxiliary jaw^s or the ma.villcp. These have a jointed structure 
and bear each a slender, jointed appendage called the 
maxillary palpus. 

Beneath the maxillse is the labium, which is in reality a 
structure formed by the fusion of a pair of organs similar 
to the maxillae and sometimes termed the second maxillse. 
The first part of this organ is called the mentuin, and is 
attached by the suhmeutum to the gula or basal part of the 
head. Attached to the mentum are the glossa and 2^«^«- 
glossce, at the sides of which are the labial palpi. 

The structure of the mouth is of special interest on account 
of the relation to the food habits. It becomes possible to 
determine from this structure what the food habits of any 
particular insect may be. Where the mandibles and maxillse 
are w^ell developed and capable of biting and tearing the 
foliage of plants, w-e may assume that the diet is herbivorous. 
How^ever, if the insect captures and devours other insects 
w^hile the mandibles appear wanting or they seem to have 
developed a suctorial tube fitted for puncturing the tissue 
of plants and animals, a liquid diet may be assumed, and it 
will follow that insects of this kind would not be affected 
by poisons applied to the surface of the plants. We have 
here then a basis for the application of poisonous solutions 
such as the arsenites, which are effective for those insects 
w^hich consume the surface of the leaf, or, on the other hand, 
for the application of oily substances for those of suctorial 
habits which enables them to secure the juices of plants 
without consuming any of the surface. For insects of this 



STRUCTURE OF INSECTS 41 

latter type we must apply substances which penetrate the 
body and close up the breathing pores, and for this, oily sub- 
stances, particularly kerosene, tobacco extract, and various 
other substances, are especially useful. The breathing pores, 
as will be seen later, are minute openings along the sides of 
the body, these being closed by minute quantities of an 
oily substance, so it is easy to see how these substances 
operate to kill the insect. 

The central region of the body, the thorax, consists of three 
distinct segments called the pro-, meso- and metathorax. 
The first of these next to the head bears the front pair of 
legs; the middle segment, or mesothorax, the second pair 
of legs and the first pair of wings; and the hinder or meta- 
thorax, the third pair of legs and the second pair of wings. 
The legs are jointed appendages adapted for walking, run- 
ning and jumping, sometimes for clinging, and consist of a 
basal segment, the coxa; a large, strong segment, the femur; 
a more slender segment, usually of the same length as the 
femur, the tibia, and the terminal portion, composed of 
from one to five small segments, called the tarsus. The 
last segment of the tarsus usually bears a pair of strong 
claws, and sometimes between these is located a disk-like 
pad or brush called the pulvillus. 

The wings, ordinarily four in number, are membranous 
expansions of the body wall and are supported by stout, 
thickened, and rod-like portions termed nerves or veins, and 
the arrangement of these throughout the wings is spoken 
of as neuration or venation. Wings are greatly modified in 
different groups of insects. In some cases they are thin 
and transparent in both pairs, as in the dragon fly. The 
front pair may be thickened or leathery, as in the grass- 
hoppers, or still more thickened, forming a hard, horny case 
(elytra), as in beetles, or partially leathery and partly mem- 
branous, as in Hemiptera. They are broad and covered 
with minute scales in butterflies and moths (Lepidoptera) , 
and the number is reduced to two in flies and mosquitoes, 
the hinder pair being aborted or modified into special organs 
called balancers or halteres. 



42 THE SIX-FOOTED INSECTS 

The abdomen or third region of the body is composed of 
about nine or ten visible segments that do not bear any 
segmented appendages, but the terminal segments are 
modified to form the external reproductive organs. The first 
seven or eight segments have on either side small openings 
into the, respiratory system, the spiracles, and there are also 
usually two spiracles located on the thorax. They are so 
small as to be scarcely visible without magnification. They 
are connected internally with the delicate respiratory tubes, 
the trachea, which extend throughout the body, so that the 
air is distributed to all of the tissues and the respiratory 
process is consequently carried on in all parts of the body. 
The minuteness of the pores, as has been already mentioned, 
makes it possible for the insect to be suffocated by a very 
small amount of oily material spread over the pores, closing 
them. 

Some further details of structure will be given in connec- 
tion with the general characters for each order. 

The internal structure of insects may seem at first sight 
to be of little relation to economic problems, but if it is 
recognized that their modes of feeding and the character 
of food depends upon the digestive organs, and their mode 
of respiration is very directly connected with certain impor- 
tant modes of treatment, and that all of their special senses 
associated with the attraction to certain kinds of plants, 
the attraction or repulsion to light or to odors, and in fact 
that the activities of the insect, as a whole, are dependent 
upon the organization, it can be realized that these structures 
have a very direct relation to their injuries and to methods 
of control. 

The digestive system of the insects is in general like that 
of all arthropods, the mouth opening being connected with 
a pharynx, the esophagus merging with the crop, commonly 
the first part of the stomach (proventriculus), in which the 
food is received and undergoes some digestive changes; 
following this the true stomach around which are a number 
of gastric ceca that secrete the gastric fluids. Following 
the stomach is the intestine, divided into the ileum, colon. 



STRUCTURE OF INSECTS 43 

and rectum, and connected with this is the Malpighian 
tubules which are excretory in function. 

The circulatory system is simple; it consists of a delicate 
tube near the dorsal wall, and in this the blood current is 
carried forward and blood circulated freely through the 
various tissues. 

The respiratory system of insects is very different from that 
of the vertebrates and in fact is of a type that occurs only 
in part of the arthropods. It consists of a great number of 
minute tubes, tracheae, which are distributed throughout the 
tissues, so that the air contained in the tubes may be 
brought in contact with tissues in all parts of the body. 
Externally these tracheae open through the spiracles which 
have been noted as located on the thorax and abdomen. 
The tracheae arising from the abdominal spiracles in most 
insects unite each side with a longitudinal tube running 
through the abdomen into the thorax, and from this lon- 
gitudinal one numerous smaller tracheae are given out, and 
these in turn divide into smallerv branches until they ter- 
minate in minute parts called tracheoles, which are so deli- 
cate that the air contained in the tubes is readily absorbed 
into the surrounding tissues. The movements of respira- 
tion are fairly rhythmetical in expansions and contractions 
of the body, expecially of the abdomen, serving to force 
the air in and out of the spiracles. Minute valves in the 
spiracular openings permit air to enter and closely hold the 
contained air, so that further contraction of the muscles 
serves to force the new supply of air out into the minute 
tracheoles. It is very evident from the structure of the 
respiratory system that contact insecticides which serve 
to close the spiracles or which may penetrate along the 
trachea and be absorbed into the tissues must serve very 
effectively for the destruction of the insect. It is for this 
reason that contact poisons, and especially oily substances, 
such as kerosene emulsion, are so efficient in the control of 
suctorial insects. 

The nervous system of the insect consists of a ladder-like 
arrangement of ganglia and fibers along the ventral wall 



44 THE SIX-FOOTED INSECTS 

of tlu' })()(ly, sej)arating at tJic anterior end, so as to pass 
around tlie eso])hat:jus, after wJiich there is a large mass, 
frecjuently termed the eerel^rum, as it oeeupies the upi)er 
l)art of the head. This ganghonic mass contains three 
pairs of gangha, while the subesophageal is composed of 
three or four, and the primitive distribution of thorax and 
abdomen is one j)air of ganglia to each segment. This con- 
dition is modified, especially in the higher insects, so that 
the ganglia may be fused, causing a single ganghon in the 
thorax, and five, three, or one in the abdomen. 

Tlie various ganglia of this system act with considerable 
independence and even dismembered parts of an insect may 
maintain their movements if the ganglia are not destroyed. 

The special senses present many diverse features as com- 
pared with higher animals, but insects give good evidence 
of possessing sight, hearing, smell, taste, and touch, although 
the exact range of these functions may differ considerably 
from the same senses of vertebrates. 

The reproduction in insects agrees for the most part with 
that of other arthropods, and except for certain remarkable 
deviations, such as are found on the aphids and bees, a 
general statement will suffice. Insects have separate sexes, 
and in a great majority of cases the males and females are 
distinct and usually may easily be distinguished by external 
characters. The reproductive organs are located in the 
abdomen, the ovaries in the central anterior part, and are 
composed of a number of ovarioles or tubular structures, 
within which the ova are developed and from which they 
pass into the oviducts. These oviducts combine near the 
end of the abdomen into a common duct leading to the 
external opening. Frequently connected with this common 
duct is a sac-like structure, the spermatheca, which serves 
for the retention of the spermatozoa. In the males the testes 
are located about as the ovaries, and lead by rather slender, 
more or less curved vasa deferentia to a common duct which 
leads to the external opening at the posterior end of the 
abdomen. The external organs are modified widely in 
different groups of insects, and in many cases furnish most 



THE TRANSFORMATION OF INSECTS 45 

important characters for classification. In general they 
consist, for the female, of the ovipositor, and in the male, of 
external claspers and a central intromittent organ. 

Mating, in many insects, is accomplished during flight, 
but this is by no means general. 

The eggs are fertilized in the oviduct, in most cases doubt- 
less in the common duct, or in the vicinity of the sperma- 
theca, and the spermatozoa enter the egg by way of a minute 
pore termed the micropyle, located usually at one end of the 
egg. 

THE TRANSFORMATION OF INSECTS. 

Insects, like all other animals, begin their development 
from an egg, not unlike any other forms. They pass through 
a series of more or less distinct stages in development from 
the egg to the mature or adult form. These stages are desig- 
nated for the insects in general as egg, larva, pupa, and 
imago. While dift'ering greatly in the definiteness of separa- 
tion between the dift'erent stages, it is convenient to use 
these terms in tracing the life history of any insect and in 
describing the character of each of the stages somewhat 
more in detail and considering the bearing in the connection 
with economic treatment. 

The egg is generally a comparatively small object, con- 
taining a considerable portion of yolk material and provid- 
ing for some degree of development before hatching. The 
shapes differ greatly in the difterent forms, perhaps the 
most common, and consequently the most fundamental, 
being an elongate, oval shape. Spherical forms are by no 
means scarce, and flattened spherical, elongated spherical, 
or even linear or cylindrical forms are very common. The 
greater difference may be noted in the character of the 
surface of the eggshell, which may be minutely reticulated, 
striated, punctured, beset with fine spines, and frequently 
having a distinct lid through which the larvse are to 
escape. They may be placed loosely in suitable locations, 
attached simply by a glutinous secretion, forced into the 
tissue by the ovipositor, etc. For aquatic species they may 



46 THE SIX-FOOTED INSECTS 

be arranged in clusters on tlie surface, attached to objects 
above the surface, to leaves overhanging the water, to stems 
of aquatic plants, either above or below the water line, and 
for some of the distinctly aquatic forms ])laced upon the 
bodies of the insects themselves. The period of incubation 
varies enormously, some hatching immediately upon deposi- 
tion, or, in some cases, preceding deposition, in which 
case the insect appears to be viviparous and for the other 
extreme remaining in the egg stage for many months, many 
species passing the winter in this stage. Ordinarily the 
eggs of any particular egg mass, or of any species, hatch 
with great uniformity, so that larvse will appear at the 
same time. This results at times in the very sudden appear- 
ance of larvae in startling numbers and to the uninitiated 
suggests the occurrence of some very remarkable invasion. 
Usually no nutritive material, other than contents of the 
egg, can be used during this period, but some species in 
which the eggs are forced into plant tissues and in which 
the egg covering must be very delicate, there is an absorp- 
tion of fluids indicated by the distinct increase of the size 
of the egg prior to hatching The hatching of the egg is 
usually accomplished simply by pushing off of the egg-cap 
or rupture of the egg membrane, but in some species it 
depends upon external factors associated with the future 
history of the larva. For instance, the eggs of the horse 
bot fly are hatched only upon the application of friction 
or moisture and warmth, conditions w^hich are brought 
about when the horse licks the hair bearing the eggs and 
thus provides ready means of transfer from the eggshell 
to its mouth, thus providing the necessary conditions for 
future development of the insect. The particular method 
of hatching may therefore have very important relation 
to preventive or remedial measures. 

The larval stage is the active feeding stage during which 
the growth of the insect occurs, and during this period there 
are a varying number of moults, most frequently from four 
to five, at which there is a rapid increase in size, the larva 
accommodating itself to the tough, chitinous body wall, 
which as soon as hardened is incapable of any expansion. 



THE LENGTH OF THE LARVAL PERIOD 47 

The larvse present the most diverse characteristics for the 
different groups of insects, and vary extremely even for 
closely related species. There has been a distinct adapta- 
tion to conditions during this stage, and larvae with slightly 
varying habits have doubtless been affected by natural 
selection in the same manner as adults have been affected 
by their particular environment. 

THE LENGTH OF THE LARVAL PERIOD. 

The length of the larval period is also in a wide degree 
an adaptation of this kind, which is frequently of the utmost 
importance in economic treatment of the species. 

The pupa stage is the connecting stage between the larva 
and the adult, and may be similar to larval form or differ 
markedly from it, according as the insect has incomplete 
or complete metamorphosis. While in some forms it may 
feed to some extent, the more common condition is that of a 
quiescent non-feeding period. During this stage, however, 
important internal changes occur which lead to the maturing 
of the insect. For those forms which have a perfectly 
quiescent pupa stage, various forms of cells are made within 
which the pupation occurs, others secrete themselves in 
rubbish, folds of leaves, crevices or cracks in bark, while 
some construct a tough, silken cocoon as a permanent 
protecting case. 

The adult stage or imago differs usually from the preced- 
ing stage in the acquisition of well-developed wings, except- 
ing, of course, in the wingless forms, and especially in the 
maturity of the organs of reproduction. The period of 
life varies in the adult also in quite a degree for species 
living over winter and others for varying periods, although 
more commonly the adult perishes soon after the comple- 
tion of the reproductory process. To indicate the various 
forms of adults would be to review all the different groups 
of insects, and hence need not be attempted even in brief. 

A very distinct grouping of insects may be made with 
reference to the definiteness of transformation. Those 
which develop without marked changes between the different 



48 THE SIX-FOOTED INSECTS 

stages are said to have incomplete metamor])li()sis (hetero- 
metabolie). Those which have very striking or marked 
(Hfferences between these stages, inchicHng the (Hstinctly 
(juiescent, non-feeding ])n])a stage, are said to have comj)lete 
metamorphosis (hoh)metahoHc). A third group is sometimes 
noted for the primitive forms in which no change whatever 
occurs, and in which no wings have developed, they being 
said to be without metamorphosis (ametabolic). 

A reference to some of the common injurious species, 
in which the different stages are shown, will illustrate these 
different phases of development. 

CLASSIFICATION OF INSECTS. 

At this point it is well to discuss in a brief way what is 
termed the classification of insects. When we speak of 
the different members of the animal kingdom or describe 
some particular insect it is quite important that we have 
and use a name which would be distinctive for that one 
form. The general practice is to use two names for each 
insect, namely, the genus name and the species name. 
A species includes those w^hich are similar in habits and 
characteristics and that may interbreed as a species or a 
kind. A genus includes a number of species and a group of 
genera with more general similarities form a family, and 
families are grouped into orders. The order then is the 
more general group and the class insecta includes about 
twenty orders. 

Apterygota (Primitive Wingless Insects). 

Order 1. Thi/sanura, Bristle tails; Campodea, Lepisma. 
Order 2. CoUemboIa, Spring tails; Podura, Smynthurus. 

Pterygota (Winged Insects). 
With Incomplete Metamorphosis. 

Order 3. Orthoptera; Cockroach, locust, cricket, mole 
cricket, "walking stick," "walking leaf." Biting mouth 



CLASSIFICATION OF INSECTS 49 

parts. Anterior wings usually shorter and firmer than those 
behind, or modified into wing covers. Both pairs are some- 
times absent. 

Order 4. Dermaptera; Earwigs. Biting mouth parts. 
Anterior wings small; hind wings large, but folded both 
longitudinally and crosswise. Posterior forceps. 

Order 5. Plecoptera; Perla. Biting mouth parts. Two 
pairs of wings or none. Larvae aquatic. 

Order 6. Ephemerida; May flies. Adult mouth parts 
degenerate and rarely used. Fore wings large, hind wings 
small or absent. Larvae aquatic, with biting mouth parts. 

Order 7. Odonata; Dragon flies. Biting mouth parts. 
Two pairs of large unfolded wings. Larvae aquatic. 

Order 8. Isoptera; Termites. Biting mouth parts. 
Wings often wanting. Social in habit. 

Order 9. Corrodentia; Book lice. Psocids. Biting mouth 
parts, wings often wanting. 

Order 10. Mallophaga; Bird lice. Parasitic, wingless, 
with biting mouth parts. 

Order IL Thysanoptera; Thrips. Suctorial mouth parts. 
Wings very narrow, often rudimentary or absent. Only 
three or four pairs of stigmata. Concentrated nervous 
system. 

Order 12. Hemiptera; Phylloxera, aphides, scale insects, 
cicadas, bugs, water scorpions, lice. (Male scale insects 
(coccidae) have complete metamorphosis.) Mouth parts 
adapted for sucking and piercing. Two pairs of wings or 
none. No compound eyes in parasitic forms which are 
degenerate in several respects. 

With Complete Metamorphosis. 

(Holometabola.) 

Biting Mouth Parts (Mandibulate) . 

Order 13. Neuroptera; Ant lions, lace-winged flies. Two 
pairs of glassy wings with many nervures. Larvae sometimes 
aquatic. 



50 THE SIX-FOOTED INSECTS 

Order 14. Mccojjfcra; Scorpion flies. Two j)airs of narrow, 
membranous wings or none. Larva^ caterpillar-like. 

Order 15. Trichoptera; Caddis flies. Hind wings usually 
larger than fore wings, both folded like fans. The body is 
hairy, rarely scaly. The larvae are somewhat caterpillar- 
like, usually live in the water in special cases, and are 
apneustic. 

Order 16. Coleoptera; Beetles. Fore wings modified into 
wing covers, hind wings folded when not in use. Larvae 
ver}^ diverse, generally with feet. The little bee parasites 
Strepsiptera are probably allied. 

Suctorial Mouth Parts (Haustellate) . 

Order 17. Diptera; Two-winged flies. Mosquito, midge, 
gnat, gad fly, house fly. Sucking mouth parts, but some- 
times with power of biting. Two anterior transparent, 
unfolded wings and posterior "balancers" or "halteres." 
Larva usually a footless maggot, without a distinct head. 

Order 18. Siphonaptera or Aphaniptera; Fleas. Wingless. 
Xo compound eyes. Ectoparasitic. Larva a footless 
maggot. 

Order 19. Lepidoptera; Butterflies, moths. Two pairs 
of uniform, scaly wungs. Larva, caterpillar. 

Mouth Parts Developed for Biting and Sucking. 

Order 20. Hymenoptera; Ants, bees, wasps, gall flies, 
saw flies, etc. Usually with four transparent wings. Larvae 
are footless grubs, except in saw flies. 



CHAPTER IV. 
LOWER PTERYGOTA. 

(Wingless Insects — Bristle Tails and Sirring Tails.) 

This group of insects includes those forms which are 
primitively wingless, there being no trace of wing structure, 









/ 


■\ 






/[ 






..■■ 






■■■■ M 










h ■ 






fe 


1 






'"' 4^^ 


i '"'- 






-^P^ 


^-\ ' 


' 


^^ii 


-...^^^^, 


— ^ 


. 


--' 






























- 



Fig. 18. — Lepisma domestica: Adult female — enlarged. (After 
Marlatt, Div. Ent., U. S. Dept. Ag.) 

(51) 



52 



LOWER PTERYGOTA 



and the evidence showing conclusively that unlike certain 
wingless forms, which are related to winged species, these 
have not had any winged ancestry. These species are 
minute, scaly, mouth parts fitted for biting. The develop- 
ment is direct, the young hatching in the form of the adults 
and developing by simple growth to the adult stage. 




Fig. 19. — Lepisma saccharina: Adult — enlarged. (After Marlatt, 
Div. Ent., U. S. Dept. Ag.) 



Order THYSANURA. 



This group, the "bristle tails," includes the forms which 
are provided wdth three bristles or bristle-like appendages 
at the posterior end of the body. The antennae are long. 



ORDER THYSANURA 



53 



slender, bristle-like, the body usually densely covered with 
overlapping scales. 



m 




Fig. 20. — Lepidocyrtus piirpureus (Lubbock): 1, dorsal view of insect; 
2, spring; 3, side view of dens showing serrations and barbed hairs; 4, 
foot; 5, side view of mucro; 6, larval form; 7, eyespot of larval form 
(From Ohio Naturalist. After Mrs. Alma D. Jackson.) 

The common bristle tail of dwellings, Lepisma domestica, 
is about one-half inch long, of a light silvery color, with 
some darker bands on the back. They run with great 
rapidity and are very smooth and flexible, so that they are 



54 LOWER PTERYGOTA 

caught with difficulty. If cauglit the scaly covcriu^^ brushes 
off readily as a hue, whitish dust. 

A related species, Lep'hsnia saccharitia, is found, especially 
in i)antries, bakeries, or in places where they can secure 
starchy materials for food. In some cases they attack the 
bindings of books or the starchy covering of labels, and may 
cause a good deal of annoyance and injury in libraries. 

Order COLLEMBOLA. 

This order, including the spring tails, is characterized 
at once by the strong spring which is folded under the 
abdomen and which catches into a loop on the thorax. The 
release of the spring from this throws the insect into the 
air with a sudden spring, which doubtless serves it as a 
protection against certain kinds of enemies. The species 
are generally found in moist places in cellars, under loose 
boards, chips, or stones, and some of them are found floating 
on the surface of water in quiet pools or along the margins 
of streams or ponds. They feed mainly on decaying organic 
matter and are of little economic concern, but a few^ species 
are credited with feeding on vegetation, especially in green- 
houses. 

THE LOWER WINGED INSECTS (PTERYGOTA). 

The remaining groups are primarily winged, and a number 
of the lower orders may be grouped together in this chapter. 

Order ORTHOPTERA. 

This order, including cockroaches, crickets, grasshoppers, 
etc., is distinguished by the biting mouth parts being rather 
simple and primitive in structure, the wings of rather simple 
pattern, the front wings narrow^ and the hind wings broad 
and folded in a fan-like manner, so as to be covered by the 
fore wings when at rest. 

They differ in their mode of locomotion, some having 
rapid running movement, using all of the legs equally well, 
others walking slowly, and others, more specialized, having 



ORDER ORTHOPTERA 



55 



the hind legs much enlarged and adapted for leaping. The 
group is conveniently divided on the basis of their move- 
ments into the running or walking and the jumping divisions. 
Cockroaches. — Of these groups the cockroaches, family 
Blattid(F, may be considered as about the most primitive 
representatives for the winged insects, the Ephemerid^, 
often placed as the lowest order, having been specialized 
in the direction of aquatic life. This position is supported 
by the primitive structure of the mouth, by the venation of 
the wings, and also by the fact that they are to be found in 
strata of the early Paleozoic era, the earliest to appear of the 
winged insects whose structure agrees quite closely with 
that of present-day cockroaches. No other winged insects 




Fig. 21,- — Ischnoptera pennsylvanica. After Lugger. 

have been found in any numbers in as early geologic forma- 
tions. Cockroaches of the present t!me seem to be persistent 
forms that have preserved ancestral characters. Their 
life history is interesting on this account. 

One species of cockroach {Ischnoptera pennsyhanica) is 
fairly common in woods under bark of dead timber and 
sometimes in houses. The females are often found with the 
egg-capsules protruding from the body. It is abundant 
all over the United States and is really an outdoor native 
species. They have well-developed wings, and often fly 
into houses and are found in stumps, under logs, etc., during 
daytime, and make migrations during the night, or in the 



56 



LOWER PrERYCOTA 



evening and early niorin'ng. They are seldom aetive during 
the bright part of the day. The egg-eapsules are bean-shaped 
and contain 50 to 60 or more eggs packed closely together, 
and after being carried some time are i)r()bably slowly 
extruded, finally left in some crevice. Tlie young hatch 
from the egg-capsules and for a time are somewhat gregarious 
and are inclined to cluster together in company with the 
adult. This may be simply an incident of location, though 




Fig. 22. — The oriental roach (Periplaneta orienfalis): a, female; h, 
male; c, side view of female; d, half-grown specimen — all natural size. 
(From Marlatt, Div. Ent., U. S. Dept. Ag.) 



it appears like maternal care. The young are similar to the 
adults in shape, much flattened, and much lighter in color, 
and the wing pads are scarcely visible. They grow by 
successive moults, and with each moult the wdng pads 
increase in size, until in the final moult they acquire the full- 
sized wings of adults. The development of the nymphs 
goes on somewhat irregularly during the summer months. 
An introduced species, the Oriental cockroach {Pcrvplaneta 



ORDER ORTHOPTERA 57 

orientalis), is a common species in houses and is responsible 
for much annoyance in kitchens and pantries. Another 
introduced species, the German cockroach {Ectohia ger- 
manica), is much smaller, but a persistent pest in houses 
and common in eating houses, bakeries, and other places 
where starchy food is available. 

The second family in the group, Mantidce, Praying Man- 
tides, have the front legs much modified for capturing insects. 
These legs have a peculiar structure. Instead of having 
short coxse with elongated tibia, the coxae are very much 
elongated. This is evidently correlated with the grasping 







Fig. 23. — Praying mantis. (After Lugger.) 

habit, and is paralleled in Emesidse and Nepidse. They are 
rather tropical in distribution, occurring in the Southern 
States. 

One species, Phasmomantis Carolina, is found to some 
extent in southern Ohio and north to Washington, D. C, 
but is rarely taken in the northern part of the United States, 
or, in general, north of 40 degrees of latitude. The pairing 
habits of the adults are rather interesting. The females 
often capture and devour the males during the process of 
courtship. The eggs are laid in large masses attached to a 
twig or some part of a plant, grouped together, lying one 



58 



LOWER PTERYGOTA 



over the other in a dense mass and exposed freely and rather 
commonly attacked by ])arasites. 




Fig. 24. — Diapheromera femorata. (After Lugger.) 



Family Phasmidae. — The Walking-stick (Diapheromera 
femorata). — The walking-stick is a common representative of 
this family throughout this part of the country. It has a 



ORDER ORTHOPTERA 59 

slender body and reduction of wings. The female is green 
and the body is thicker than that of the male. In autumn 
the bodies of the males become brown and resemble in color 
the twigs on which they are found. This species has one 
generation each year, hatching about the first of June, 
and the adults maturing in the latter part of the summer. 
The adults are found as early as the first of September. 
They are most commonly found in trees and shrubbery, 
at some little distance from the ground. Eggs are simply 
dropped from the trees or shrubs on which the adults are 
resting, and instances are cited where they are so abundant 
that the dropping of their eggs makes a sound like the 
falling of rain. The eggs rest on the ground and are pro- 
tected more or less completely by leaves. They retain 
their vitality through winter and early spring and hatch 
in early summer. This represents a rather simple life-cycle 
with an annual generation and one in which the winter is 
passed in the egg stage. When these insects are so abundant 
as to be injurious, it would be of service to rake up and 
burn leaves, but they are not usually abundant enough to 
do any great damage. Another way would be to spray the 
trees with arsenical poison at the time the young are feeding. 
They are leaf-feeding forms and would secure the poison 
with their food. A grass-feeding species. Monomer a blatch- 
ley, occurs in the Mississippi Valley. 

Some of the tropical forms are more striking than this 
native variety and show more forms of mimicry. One form 
has wings in form and venation like the leaves of certain 
plants, so that the insect is remarkably well protected. 
Other forms simulate growths of lichens, etc. The whole 
family seems built on the plan of representing protective 
resemblances. Several species have the same form as the 
walking-stick, but possess short wings. There is a wide 
divergence in wing development. 

The Locusts {Acrididcp). — The locusts include some of the 
most important economic species. They are great pests in 
some parts of the country. The group includes the old-world 
migratory locusts, which still appear as an occasional plague 



60 LOWER PTERYGOTA 

over some parts of northern Africa. The old-world species 
is represented in this country most nearly by tlie western 
migratory locust or the grasshopper of the western plains, 
Melanoplus spretus. This western species, the devastating 
locust, is far less destructive in the aggregate than one or 
two other species, but has attracted more attention because 
of complete devastation which follows its appearance. 
There is one species in Argentina that has attracted a great 
deal of attention and has been a great menace to the crops 
of that country. 

The Devastating Locust. — The devastating or Rocky 
INIountain locust, is limited in its normal distribution to the 
plateau region of the Rockies, the normal conditions for its 
survival being the high altitude, dry atmosphere, and a 
supply of grassy vegetation. They are most dependent on 
the bufi'alo grass or other native grasses. The species became 
important during the days of early settlement of that portion 
of country just east of the mountains, because at times, 
when vegetation ran short in its native breeding ground, it 
migrated sometimes 300, 400 or 500 miles, reaching places 
that were settled and proving extremely destructive to 
growing crops. During the late 70's they were such a serious 
source of injury that a very decisive effort was made to 
work out their habits, life history, and means of suppression. 
It is now generally assumed that it is only under conditions 
when it becomes extremely abundant and must migrate that 
it causes serious devastation outside of its regular breeding 
ground. 

The adults may fly long distances and after finding suit- 
ble places for depositing eggs, bore into the ground with 
the ovipositor and abdomen for one and a half or two inches. 
The process consists of merely pressing the earth away by 
the ovipositor, and denotes a great degree of power because 
the eggs are preferably deposited in hard ground where 
the soil is packed. The eggs are coated with a glutinous 
secretion which protects them from the weather and they 
remain in these little burrows through autumn and winter 
and hatch early in spring. Sometimes they hatch before 



ORDER ORTHOPTERA 



61 



there is much vegetation and sometimes the young are killed 
off in large numbers by late frosts. The young develop 
pretty rapidly and are able to travel quite considerable 
distances, especially if vegetation is scarce. They acquire 




Fig. 25. — Melanoplus femur-ruhrum, female. (After Lugger.) 



wings often as early as the latter part of June. Flights may 
occur as early as July and often in August and September. 
Migration probably occurs rather sparingly unless food 
supply is scanty. 



62 LOWER PTERYGOTA 

We lia\e se\'eral species in the eastern United States closely 
related to the Rock\' Mountain species. The most common 




Fig. 20. — Mclanoplus atlanis, male. (After Lugger.) 



Fig. 27. — Melanoplus atlanis, female. (After Lugger.) 

is the red-legged grasshopper {Melanoplus femur-mhrum) . 
It is similar to the Rocky ]\Iountain species, but is not cap- 



ORDER ORTHOPTERA 



63 



able of any sustained flight. There is seldom anything like 
a general migration. They will travel out of dry pastures 
into corn, wheat and oat fields, and sometimes injure apple 
trees. Their ordinary habitat is in pasture or meadow and 
grass is their most common food. This species is abundant 
all over the eastern United States; is an economic factor 




Fig. 28. — The yellow- winged locust (Camuula pellucida): a, adult male; 
b, female; c, nymph — somewhat enlarged. (After Simpson, Div. Ent., U. 
S. Dept. Ag.) 



year after year, and undoubtedly causes more damage than 
the Rocky Mountain species. They do not usually destroy 
the grass completely, but take a large share of the crop. 
If they were eliminated the same acreage would supply 
more hay, or support more cattle or other stock in pasture. 
Plowing the ground where eggs have been deposited, rota- 



64 



LOWER PTERYGOTA 



tion of crops, and the catching of the newly hatched hoppers 
in early summer before the damage has been done are 
measures that will assist in keeping them in check. They 
are preyed upon by several parasitic and predaceous insects 




Fig. 29. — Trimerotropis maritima, female. (After Lugger.) 

and by spiders and birds as well as fungous diseases, which 
together serve to hold their numbers down. 

iVnother very similar species, but with longer wings, and 
which occasionally has a migration, but probably not so 



ORDER ORTHOPTERA 65 

uniformly destructive, is Melanoylus atlanis. The wings 
are long and the capacity for flight more like Melanophs 
spreius, but flight seldom reaches more than a few miles. 

The Beach Locust {Trimerotropis maritima). — The beach 
locust is an interesting species that occurs along the coast 
of the ocean as well as fresh-water lakes or where sand dunes 
are common. The coloration and markings are very dis- 
tinctly adapted for protection and the nymphs are really 
about as well protected as the adults. They are conspicuous 
on the wing, part of the wing being bright yellow in color, 
but when they alight on the sand they immediately disap- 
pear on account of the color and markings. They must 
feed on grasses in such locations and are often found around 
clumps of Juncus and Arenaria, but rarely seen feeding. 




Fig. 30. — Trimerotropis maritima, male. (After Lugger.) 

This species is found in June and July in the larval and 
nymphal stages, and in different sizes, some comparatively 
small, representing the second and third moult. Their 
moults occur fairly rapidly during this particular time. 
There is some difference in the time of hatching from eggs, 
and adults are to be found by the early part of July. The 
time varies in different seasons. Later in summer there will 
be very few larvse and a large number of adults, and still 
later only adults. The adults remain active and travel 
over the sand for several weeks. They make characteristic 
tracks on the sand, easily detected. They probably do not 
5 



66 



LOWER PTERYGOTA 



mate until somewliat late in the season, seldom during mid- 
summer, but probably by the latter part of August. 

In regard to the deposition of eggs, it would seem that 
they must select rather solid parts of the sand, but egg 
masses have not been found. There is no way for the 
nymphs to travel any great distance. The eggs must be 
deposited during the autumn months, probably in September 
and October. They survive the winter protected in the 




Fig. 31. — Dissosteira Carolina, female. (After Lugger.) 



sand or in places where there is more solidity in the soil. 
The eggs hatch in the spring, probably in June, some perhaps 
in May. It does not seem necessary for them to adjust 
themselves particularly at this stage to any conditions, for 
the life-cycle can be carried through easily in summer. 
There is one generation a year. 

The more common form is a rather light gray, with the 
spots of a rusty color, and some spots of darker color, a granite 
combination, resembling the surface of the sand. Another 



ORDER ORTHOPTERA 



67 



fairly common form has a brownish band or stripe on the 
upper part of the thorax or wing covers, and making a promi- 
nent Hne when the wings are closed. It occurs about as 
commonly on the sand, but may have a preference for places 
where there are little sticks. A less common form is lighter 
colored, almost ochre yellow, and more common among 
grass, leaves, and clumps. The color is close enough to the 
general color of the sand to afford some protection on the 
bare sand. 




Fig. 32. — Arphia sulphurea. (After Lugger.) 



Family Locustidse. — The family Locustidse includes insects 
which are usually green in color and called green grasshoppers 
or meadow grasshoppers, katydids, and stone crickets. 
They are characterized by great length of antennse, the width 
of wings, and generally a green color. They are common 
among the coarse grasses along the roadsides and in 
meadows. A rather striking group includes the sword- 
bearers, Conocephahis, the striking feature being the form of 
the head, which is extended in a prominent horn, varying 
somewhat in size and shape in different species and with 
long, slender antennae. The wing covers are somewhat 



68 LOWER PTERYGOTA 

sword-shaped and the ovipositors also have a sword-Hke 
shape. They are found during the latter part of the summer 
as adults, occurring on grasses and low vegetation, but 
seldom on shrubby plants or trees. The females use the 
long, sword-shaped ovipositor for thrusting eggs into the 
tissues of plants, and thus they are protected during the 
winter time. The eggs hatch in the spring and larval devel- 
opment occurs during the early summer, the adults appearing 
in the middle or latter part of summer. 

Katydids. — ^The katydids include several species, but 
the one most properly called katydid has broad, concave 
wings with rather prominent veins, quite strongly concave. 




Fig. 33. — Conocephalus ensiger, female — natural size. (After Lugger.) 

The name of the species is Cyrtophyllum concavum. They are 
noted for their song, and sing particularly during the twilight 
and early part of the night. This species is the best singer 
of the katydids. Their life history is practically the same 
as that of Conocephalus. 

A species nearly related to this is the angular-winged 
katydid, which deposits eggs on the surface of twigs, the 
eggs overlapping each other like tiles on a roof. 

Stone Crickets. — In this family also have been placed the 
stone crickets. Most of them are included in the genus 
CeuthojMlus. Quite a large number of species is included 
in this genus. They have changed from the food habit of 



ORDER ORTHOPTERA 69 

the other members of the group, and instead of feeding upon 
ordinary vegetation they secrete themselves in dark places 
and feed upon debris or decaying organic matter occurring 
in such places. The character of the ovipositor is like that 
of the crickets, but the head, antennae, and other parts 
look like those of field locusts. The details of their life his- 
tory are not fully worked out, but it is probable that there 
is one generation a year. 

Family Gryllidse. — This family includes the crickets and 
may be separated into herbivorous, carnivorous, and omniv- 
orous forms. 

Oecanthiis, tree crickets. Oecanthus iiiveus, snowy tree 
cricket, is most commonly referred to, but 0. fasciatus and 
other species are more common. The larvae feed upon plant 
lice and are distinctively carnivorous, and therefore are 
serviceable during that stage. The adults may feed on flies, 
but were formerly thought to be herbivorous. The adults 
are found in autumn, and then they gather on various kinds 
of trees, fruit trees, etc. Th-e eggs are forced into the twigs, 
forming a series of punctures. The eggs are deposited in 
two rows. They are elongated in form, and the masses of 
eggs include forty or fifty eggs deposited by each individual. 
The eggs remain in the twigs during the winter and are well 
protected in that way. They are sometimes deposited in 
galls on willows; if not by this species by one closely related. 
Some eggs are forced into the stems of annual plants, Helian- 
thus, Solidago, etc. The eggs hatch during the spring sea- 
son and the larvse depend upon plant lice for food supply. 
They grow to reach adult stage, when they probably feed 
upon other insects. They are probably not destructive, and 
the attacks upon plant lice make them valuable. They are 
rather desirable on fruit trees, only in some cases the punc- 
tures of the twigs result in rather severe pruning. 

A quite common species on Helianthus is Oecanthus fas- 
ciatus. There are four or five species that look a great deal 
like the common forms. In the males the wings are broader 
and very transparent. One form lays eggs in separate punc- 
tures at different points. 



70 



LOWER PTERYGOTA 



The mole crickets are extremely specialized as subter- 
ranean forms. They burrow in the earth and have become 
adapted to this habit. They have a dense velvety covering, 
which is doubtless serviceable as a protection against mois- 
ture, etc. In one species the wings are considerably reduced, 
but in another species they are longer. In all the species 
the legs are well developed, and are excellent for digging and 
burrowing, with toothed arrangements for pushing into the 
soil, much as in the mole and other digging animals. These 
teeth are mostly on the tibia. The tarsi are rather slender. 
Almost the same kind of structures occur in certain beetles 




Fig. 34. — Gryllotalpa Columbia: a, side view of anterior claw; b, the 
same of G. borealis. (After Lugger.) 

and in burrowing Hemiptera. The mole crickets feed on 
vegetation, especially tuberous roots of plants; sometimes 
they dig into potatoes. Ordinarily they are not abundant 
enough to attract much attention. The long-winged form 
flies at night and sometimes flies into houses. They are 
completely covered with a fine pile, as velvety as that of a 
mole, and are also as well fitted for burrowing. 



EUPLEXOPTERA (DERMAPTERA). 

Earwigs. — ^The earwigs, or Euplexoptera, are characterized 
by the presence of four wings, the first pair of which are very 



EUPLEXOPTERA 



71 



short, veinless, and meeting in a straight hne when at rest, 
the second pair of which fold both lengthwise and crosswise; 
biting mouth parts; forceps-like caudal appendages; incom- 
plete metamorphosis. 




Fig. 35. — Labia minor. (After Lugger.) 



These forms resemble rove beetles in appearance, being 
very long and slender, but differ in having the caudal appen- 
dages. They are found in the southern part of the United 
States and on the Pacific Coast, and are very common in 
parts of Europe, where they are troublesome, because of 
their habit of feeding on flowers and fruits. 



72 LOWER PTERYGOTA 

A common species in the northern states is Labia minor, 
which occasionally may be seen flying in large numbers 
around barnyards. It has not occasioned noticeable injury, 
however, and is not counted of special economic importance. 

Order PLECOPTERA. 

This group includes the stone flies, and the species are 
all aquatic, but in general characters they are pretty closely 
related to the Orthoptera. The mouth parts are mandibu- 
late, the front wrings are narrower than the hind wings, which 
fold together and are covered by the front wings when at 
rest. The transformations are incomplete, the larvse dis- 
tinctly aquatic and provided with tracheal gills along the 
side of the body, which permit them to absorb oxygen from 
the water. The species have an importance as a source of 
food supply for aquatic animals, and in some localities they 
probably furnish a considerable support for certain kinds of 
fishes. 

The adults are usually found in the vicinity of water, on 
tree trunks or rocks, but except as they may attract atten- 
tion they have no particular importance. Unlike the May 
flies, they are not strongly attracted to light, and are seldom 
noticed except in their native habitat. 

Order EPHEMERIDA. 

May flies form an order frequently placed as the lowest 
of the winged insects. While showing some simple structure, 
we may consider their simplicity due to reduction or speciali- 
zation. The mouth parts of adults are reduced, fore wings 
large, hind wings small. They are specialized in the aquatic 
habit of the larval stage. The genera and species are not 
particularly numerous. The name Ephemera was applied 
on account of their very short apparent life. They are 
developed from aquatic forms that have a period of develop- 
ment of from one to three years, but have a very short life 
in the adult stage. There are many species that come out 



ORDER EPHEMERIDA 73 

toward evening and fly for an hour or two, deposit their 
eggs, .and then disappear. Other species Uve for several 
days, some perhaps for a week or two. Their first flight 
is in what is called the pseudimago stage. When coming 
to rest they attach themselves to some convenient object, 
and there the skin of this stage splits and the insect escapes, 
leaving the skin still clinging to the object. After this 
moult they are mature adults with full-sized wings, but with 
a difference in texture, and in genital organs, which are not 
fully developed in the pseudimago stage. For many of the 
species it is probably safe to say that they mate the same 
day that they come out of the pseudimago stage. The 
normal method of mating is on the wing. Eggs are probably 
deposited within a day or two, being laid either on the 
surface of the water or else underneath the surface. This is 
done by the adult folding the wings and descending beneath 
the surface. In one species the eggs are extruded in long 
packets and then the insect descends close to the water and 
deposits them on the surface. 

The eggs after deposition in one way or another — in or 
on the water — hatch in a short time and the larvse grow and 
probably migrate more or less in the water. They do not 
have to come to the top of the water for respiration, as they 
are fitted with organs which provide for aquatic respiration, 
and probably live two or three years in the water. The 
adults appear every year, and if the larvae require two or 
three years to grow, there must be different broods, and if 
there are two or three different generations in the lake, there 
must be an enormous shifting of its population. They con- 
stitute an enormous body of animal life, furnishing the basis 
of food supply for other forms of animal life, fishes, etc., 
which in a few days shifts its position and disappears, thereby 
lessening the food supply materially. The larvae of these 
nymphs come to the surface and the skin splits and the 
pseudimago form issues and flies. The exuvise or skins which 
are left on the surface drift in on shore and pile up in wind- 
rows on the beach. 



74 LOWER PTERYGOTA 



Order ODONATA. 

This group includes the dragon flies and damsel flies, 
insects with incomplete metamorphosis, biting mouth parts, 
and large, net-veined wings without folds. 

The larvae of these dragon flies and damsel flies are aquatic 
and distinctly predaceous, feeding on aquatic animals. 
The adults are also predaceous and catch insects in flight 
very readily. The former, particularly, have very swift, 
rapid flight, and may be seen darting here and there, espe- 
cially in the vicinity of water, while the latter fly somewhat 
more slowly. Both groups catch insects and feed upon 
them, and so they are thought of as being beneficial, since 
many of the insects that they feed upon are destructive. 

The eggs in all cases are laid close to the water's edge, 
either at or jusc above the surface, or in some cases attached 
to stems of water plants beneath the surface. When the 
larvae hatch they are already under water and can begin 
their active life, preying upon the aquatic animals. In 
both adult and larval stages the mouth parts are provided 
with strong mandibles fitted especially for biting. In the 
larval or nymphal stage there is a very peculiar enlargement 
and elongation of the labium, so that it becomes a large 
mask for the front part of the head, covering the outer 
mouth parts and lower part of the face. These are provided 
with a pair of very strong, clasping, or pincer-like organs, 
which are used in capturing the aquatic animals on which 
they prey. The elongated and jointed structure of the 
labium permits the insects to thrust this forward a distance 
of about half an inch from the head, so that they can reach 
out and capture animals that, seem to be out of their reach. 
These are snatched up very quickly and ground up with 
their mandibles. 

After passing the larval stage they crawl out of the water 
on the bank of the stream or pond or sometimes on the stem 
of a plant, then the nymphal case splits along the centre 
line of the back, the adults draw themselves out of this 



ORDER DO NAT A 75 

case, their wings expanding rather slowly or gradually. In 
about a half-hour they are ready for flight. 

Their very rapid movements and habits have given rise 
to a number of common names. Aside from the dragon 
fly they are called mosquito-hawks, which is quite appro- 
priate on account of their feeding on mosquitoes. Sometimes 
they are called snake feeders or snake doctors. In the 
past the name devil's darning needle was quite popular, 
although not used much at present. It was said that they 
sewed up the ears of untruthful children. 




Fig. 36. — Dragon fly Libellula pulchella. (Photo by author.) 

These different common names illustrate different popular 
interest in the group and forms of superstition. These 
insects seemed to inspire a great deal of dread before their 
life history and habits were known definitely. 

The group Odonata can be looked upon as being very 
useful and serviceable to mankind, as they feed on destruc- 
tive insects, mainly mosquitoes and many aquatic organisms. 
Of course they feed on useful insects as well as detrimental 
ones, but it is generally believed that the majority are detri- 
mental ones. 



76 



LOWER PTERYGOTA 



Throughout a large part of the country is found the 
handsome LibeUuIa j)uchella, shown in Fig. 36. It is a 
large species with pruinose body, and the wings are each 
conspicuously marked with three black patches. This 
species is seen very frequently flying over low meadows and 
in the vicinity of ponds and rivers. Judging by the abun- 
dance of the adults it must be one of the quite important 
species as affecting the aquatic life, and the adults must 
dispose of many troublesome pests. 




Fig, 37, — Leucotermes flavipes: a, adult male; b, terminal abdominal 
segments of same from below; c, same of female; d, male, side view, some- 
what inflated by treatment with ammonia; e, abdomen of female, side 
view; /, tarsus, showing joints and claw; a, d, e, enlarged; b, c, f, greatly 
enlarged. (After Marlatt, Div. Ent., U. S. Dept. Ag,) 



Order ISOPTERA. 

This order is characterized particularly by the thickly 
net-veined wings which fold flat upon the back and by the 
biting mouth parts and incomplete metamorphosis. 

The order includes one family, the Termitidse, in which 
there is a remarkable separation of habits, the species living 
in communities and showing much the same kind of adap- 



ORDER ISOPTERA 



77 



tation for community life as is shown in the ants. The 
colonies usually include a large number of individuals, but 
may vary from a few dozen to many thousands. Each 
colony also includes several kinds of individuals, some of 








a 



Fig. 38. — Leucotermes flavipes: a, queen; 5, nymph of winged female; 
c, worker; d, soldier. All enlarged. (From Marlatt, Div. Ent., U. S. 
Dept. Ag.) 



which are neuters, while others represent the males and 
females of normal species. The males and females are 
winged at time of maturity, but the wings are broken off 
after flight, and thereafter these individuals, like the neuters, 



78 



LOWER PTERYGOTA 



ai)])car to be wingless, altlioiigli the stubs of the broken-oflf 
wings may be noted. At tlie time of flight the different 
individuals come to rest at different places, so that they 
are pretty generally distributed. They then set to work 
to form a new colony. This, however, is impossible unless 
some of the workers are also located at the same place. 
It often occurs that many die oflF, without establishing a 
new colony, for lack of workers. 

The colonies are located in the earth, or for some species 
upon the trunks of trees, or in some of the tropical forms 




Fig. 39. — Leucotermes flavijjes: a, newly hatched larva; b, same from 
below; c, egg. All enlarged. (From Marlatt, Div. Ent., U. S. Dept. 

Ag.) 



large ant hills are built above ground which accommodate 
immense numbers of individuals. 

The white ants feed upon wooden fiber and make attacks 
upon trees or upon dead timber and are especially destruc- 
tive to wooden structures, so that in regions where they are 
abundant they constitute a very serious menace to wooden 
structures. They also feed very extensively upon wooden 
furniture, books or papers in places accessible to them, and 
the damage occasioned by such attacks is often very exten- 
sive. 



ORDER ISOPTERA 



79 



The colonies include as neuters two forms: one, the 
workers, having moderately large heads, strong jaws, and 
adapted for carrying on the labor of the colon}', such as col- 




FiG. 40. — Work of white ant (Leucotermes flavipes) in chestnut. 



lecting food, caring for the young, and in fact, all of the 
ordinary work of the colony. The other form, called soldiers, 
has as its special function the protection of the colonies. 



80 



LOWER PTERYGOTA 



Tliey have enormous lieads, strong jaws, and are especially 
fitted for attacking enemies that may enter the colony. 
They are, of course, helpless against larger kinds of animals, 




Fig. 41. — Termites and their work: a, adults working in the stem of 
geranium (photograph by Wm. P. Beeching, Jr., Ohio Agric. Exp. Sta.) ; 
6, enclosed gallery suspended from the underside of greenhouse bench 
(photograph by J. L. King, Ohio Agric. Exp. Sta.). 

but their bite is very severe and they doubtless in this way 
serve as very effective guards against a numerous host of 
smaller-sized animals. 



ORDER CORRODENTIA 81 

The most abundant individuals are the workers and then 
the soldiers. Both of these forms never acquire wings. 

For this region and for the eastern and southern United 
States there is one common species, Leucotermes flavipes 
which is distributed as far north as the Great Lakes, to 
Boston on the Atlantic coast, and into central Illinois in 
the Mississippi Valley. The colonies of this species are 
formed, usually under old logs or stumps, and from these 
nests the termites construct tunnels, sometimes for long 
distances, to reach dead wood, buildings or other structures 
in which they can secure a food supply. Porches, fences, 
and all sorts of wooden structures suffer from their attack, 
but the greatest menace, perhaps, is to wooden trestles 
and bridges which are likely to have sudden weight thrust 
upon them. In feeding, the ants eat out the inner part of 
the timbers, leaving an exterior shell, thus it happens the 
timbers are greatly weakened before any indication is seen 
upon the surface. 

The most effective treatment is to locate the nest, give 
it a thorough treatment of bisulphide of carbon to kill out 
especially the reproductive individuals, so that the colony 
will not be able to multiply. 

Particularly the use of stone, brick or concrete foundations 
in bridges or trestles and the separation of the wooden part 
of structures from the earth in localities where white ants 
are present will serve as a prevention from their attacks. 
In tropical regions the practice is to use stone or metal, 
not only for bridges, trestles, etc., but in many places for 
railway ties, in order to avoid loss from the termite's attacks. 

Order CORRODENTIA. 

Family Psocidae. — Book Lice. — These are small insects, 
a considerable number of them are entirely wingless, but 
there are many species in which the wings are fully devel- 
oped. The wings are held in a sloping position, a somewhat 
roof-like arrangement over the abdomen, but not folded 
flat, and have a rather small number of veins. Their appear- 
6 



82 



LOWER PTERYGOTA 



ance is considerably like that of the plant lice, but they 
have distinct biting mouth parts. They are totally different, 




Fig. 42.— Clothilla. 




Fig. 43. — Work of Atropos on grain. (Photo from Ohio Exp. Sta.) 



though, in their method of reproduction. The more interest- 
ing members of the group are those which are wingless 



ORDER MALLOPHAGA 83 

and occur in houses, commonly found among books, old 
papers, insect collections or herbaria, and which do a great 
deal of damage in such places. 

The common book louse, Atropos divinatoria, is most 
abundant in houses among old books. They are too small 
to be pinned, but they can be mounted on micro slides to 
good advantage, for stud}^ with the microscope. They are 
about one-sixteenth of an inch in length, rather flat, nearly 
white, antennae slender, and eyes quite small. Their man- 
dibles are strong and they feed on the mucilage and glue or 
paste of book bindings, on the tissues of preserved insects, 




B 

Fig. 44. — Atropos divinatoria. 

and they are quite detrimental to collections of plants in 
herbaria. 

They may be destroyed by fumigating with bisulphide 
of carbon for half an hour or so. They are so very small 
that it is almost an impossibility to exclude them entirely 
from any place. 

Order MALLOPHAGA (Bird Lice). 

This order includes the biting lice infesting birds and 
mammals. They are usually hard and horny and much 
flattened. They possess mandibulate mouth parts adapted 



84 



LOWER PTERYGOTA 



to cutting and biting the hairs, feathers, epidermal scales, 
or excretions on the bodies of their hosts. The mandibles 
are situated in most forms underneath the head and near 
the centre, the clypeus projecting and forming the most 
anterior portion of the liead. TJie labrum is present and 
the maxillary palpi are prominent in a part of the group. 
The eyes when visible are located back of the antennae. 
The antennte are five-jointed except in Trichodedes, where 
they are three-jointed. The thorax is generally narrow and 



^'"% 




Fig. 45. — The common hen louse (Menopon pallidum). Greatly 
enlarged. (Banks, Div. Ent., U. S. Dept. Ag.) 



frequently but two di\'isions are apparent. The legs are 
adapted to clasping (Fhilopterida^) or to running (Liothe- 
idse), the tarsi in the first case being short and in the latter 
case being long, well adapted to running, and provided 
with two claws. The members of the first division occur 
on both mammals and birds, those of the second, except 
Gyrojms, are limited to birds. Wings are entirely wanting, 
and the abdomen contains nine or ten segments and is 
usually oval in shape. 
The eggs are glued to the hairs or feathers of the host 



ORDER MALLOPHAGA 



85 



animal and open with a circular cap or lid at the free end. 
The larvae are less flattened, shorter in proportion, and 
without the hardened parts common to the adults, covering 
a part or all of the surface. The length of life and rapidity 
of multiplication has not been determined accurately for 




Fig. 46. — Trichodectes scalaris (biting cattle louse). (Bull. 5, Fig. 134.) 



these insects and the habits of the insects make any such 
determination a matter of considerable difficulty. 

While it is, of course, very desirable that a more complete 
knowledge of the life history of the species be secured, it 
may be considered as already established that all the species, 
with no known exception, pass their transformations on the 
body of the fowl, and that, unlike the mites, they may be 



86 LOWER PTERYGOTA 

attacked witli the assurance that e^<j:s and newly hatched 
young are not developing in some out-of-the-way corner. 

Moreover, the observations made on the length of time 
required for the hatching of the eggs indicate that they 
require a number of days at least, so that in repetition of 
treatments intended to kill individuals hatched since a 
former treatment a period of ten days to two weeks may be 
counted on as probably short enough. 




Fig. 47. 



-Trichodecies parumpilasus (biting horse louse). (Bull. 5, 
Fig. 133.) 



It should always be borne in mind that lice must grow^ 
from eggs laid by the adult louse, and can never originate 
from filth or other matter. Chickens hatched in an incuba- 
tor should be absolutely free from lice and remain so until 
brought in contact with a lousy hen or put in a lousy chicken 
house. 

The effect of these lice may be less important than the 



ORDER THYSANOPTERA 87 

suctorial lice, or the sucking ticks or mites; but judging 
from the serious results following the efforts of the animals 
to rid themselves, and from the known irritation due to 
anything crawling among the hairs or feathers, it cannot be 
doubted that they cause much annoyance and inconvenience 
to the creatures that become their involuntary supporters. 
The biting lice of cattle and horses are annoying pests 
and demand the attention of the stockman. 

Order THYSANOPTERA. 

The species of this order are all very small and have 
mouth parts intermediate between the biting mouth parts 
of the Orthoptera and the suctorial mouth parts of the 
Hemiptera. In some respects they may be considered as an 
intermediate group between the Orthoptera and the Hemip- 
tera, but not as a distinct connecting link between the two, 
because in the matter of wings they have a specialization 
of their own. They are minute, all very small, the largest 
not over one-eighth to one-fourth of an inch in length. 
Many are not over one-sixteenth of an inch long. They 
have very slender bodies and slip around readily between 
the parts of the blossoms of many different kinds of plants. 
The different stages may occur in the bloom, and they feed, 
at least in large part, upon the soft tissues of the parts of 
the blossoms, puncturing and corroding them so as to secure 
the juicy contents. 

The mouth parts are drawn out in style-like form. Their 
structure is partially like that of Hemiptera, but the styles 
are not produced beyond the length of the head. They are 
not capable of cutting and biting as the mouth parts of the 
grasshoppers, nor are they strictly suctorial organs. The 
wings are characteristic. In one division the wings are 
narrow, with few veins and provided with quite long marginal 
setae which furnish a large part of the area of the wings. 
The hind wings of this form also have setse but no veins. 
Another division has wings very simple, without any vena- 
tion, and provided with enormously long setse. They are 



88 LOWER PTERYCOTA 

l'rin<;r-\vi !!<;'('( 1 forms, a clianictoristk" striR'ture. Anotlier 
character almost equally distiiK'tivc is found in an aborted 
tarsal joint modified into a bladder-like ex])ansion of tlie 
tarsus. This joint is evidently a modifieation from the 
orchnary form with claws. Bladder-foot is one term appHed 
to this iijrou]) and riiyso])oda is the name fjjiven in some text- 
books, based on tliis ])arti('ular structure. 

Tlie life liistory of tJie grouj) in general is ratlier sim])le. 
Tlie adults deposit eggs at different periods tlu'ougli tlie 
summer, the generations })eing somewhat irregular, often 
tliree or four in a summer. TJie eggs are ratlier large for 
tlie size of the insect and somewhat ovoidal or oblong in 
shape, almost transparent. They are deposited on the 
foliage or bloom of ])lants, and hatch quite promptly. The 
larvie develoj) gradually by successive moults, without 
any striking metanior])hosis, until they reach the adult 
stage when wings are developed. Ik'tween the larval and 
adult stages is a stage of quiescence; parts, including the 
antennae and legs, are almost immovable. This may be 
looked upon as a develo])meiit along the line of the more 
striking metamori)li()sis in other cases. The eggs are 
deposited by nieans of an ovipositor that differs in the two 
subgroups of the family. In one case there is a saw-like 
ovipositor with blades that glide on each other and enable 
them to i)ush eggs into soft tissues. In the other division 
the ovipositor consists of the elongated tubular abdominal 
segments. The latter is a more sim])le condition, but the 
former is more primitive. The latter probably results from 
reduction, the saw-like structure being lost. The difl'erence 
in egg dejKisition amounts sim])ly to position in which 
eggs are laid: in the first instance they are laid more or less 
within the tissue, in the second instance on the surface. 

For the first grouj), Terebrantia, the common Thripidse 
occur in clover, Comi)osita\ apple blossoms, milkweed, etc., 
also in wheat blossoms. The food plant is determined simply 
by the flowering season. The most abundant is the wheat 
thri])s, Thri])s tritici; this is an economic sj)ecies, causing 
some damage. 



ORDER THYSANOPTERA 



89 



In the spring they are found in apple bloom and a large 
proportion of the blossoms are infested, as high as 80 per 
cent, in one instance having been observed to be so damaged 
as to render blossoms infertile. They also occur commonly 





Fig. 48 Fig. 49 

Fig. 48. — The pear thrips (Euthrips pyri) : ovipositor and end of abdo- 
men from side. Much enlarged. (After Moulton, Bur. Ent., U. S. Dept. Ag.) 
Fig. 49. — The pear thrips (Euthrips pyri): larva. Much enlarged. 
(After Moulton, Bur. Ent., U. H. Dept. Ag.) 



in strawberry bloom, and the injury to the bloom appears 
to result in the distortion of the berry known as "buttoning." 
When exposed they can be killed by spraying with kerosene 
emulsion. 



90 



LOWER PTERYGOTA 



Pear Thrips [Eiiihrips pi/ri). — 'riie ])('ar tlirips has l)een 
a serious ])est in California, attac*kiii»i; beside ])ear a niiml)er 
of the relatcul fruits. Its attack is directed largely against 
the bloom and tJie loss of fruit is serious. Contact sprays 
are only partially effective, as the insect is protected so much 
of tlie time within the ])arts of the bloom. 

Grass Thrips {Aplidndfhrijhs' sfrlat(i). — 'J'lie grass thrips is 
an extremel\' abundant s])ecies in tJie northeastern United 




Fig. 50. — The pear thrips {Euthrips pijri) : nymph or pupa. Much 
enlarged. (After Moulton, Bur. Ent., U. S. Dept. Ag.) 



States, and lias been reported as destructive to oats in 
Canada. It attacks the upper part of the plant and its injury 
shows, especially in the blasting of tlie lieads of grass and 
oats. In grass this is called "silver top," a condition of 
wliitening and withering of the upper stem and seed head 
which is })rol)ably })ro(hiced by other insects as w^ell as thrips, 
but wliicli is no (h)ubt in hirge measure to be credited to 
these almost invisible little pests. 
Another species is Thrips tahaci — known now as onion 



ORDER THYSANOPTERA 91 

thrips. It occurs on quite a large variety of plants. It is 
similar to Thrips tritici in size, but different in some micro- 
scopic details. It is injurious to onions. Massachusetts, 
Iowa, Colorado, Rhode Island, and Ohio have all reported 




Fig. 51. — The pear thrips (Euthrips pyri) : adult. Much enlarged. 
(After Moulton, Bur. Ent., U. S. Dept. Ag.) 



extreme injury from this species. The degree of injury is 
determined in large part by temperature, moisture, etc. 
It occurs on many plants besides onions. In dry seasons 
it becomes very injurious to the onions. The leaves wilt 
and show whitening, and the injury is easily recognized. 



92 LOWER PTERYGOTA 

The life liistory is a matter of adaptation to different 
plants. There are pr()l)al)ly several jjjenerations in one 
summer and hibernation in mature larval or adult stage. 

Mullein Thrips {Phloeothrips verhasci). — The mullein thrips 
has a definite restricted food plant and the herbivorous 
character of the insect can be easily established. It is a little 
black species found in mullein plants the year through. 
In early spring they are found among the bases of the mullein 
leaves. They seldom try to fly, but creep about among the 
fine hairs of the mullein leaf. They are very common in the 
mullein plants and there are very few plants without them, 
so examples may almost certainly be found wherever mullein 
occurs. The eggs are laid soon after the leaves are well 
started in the spring and there is a pretty definite brood. 

The adults of this brood mature about the time the blos- 
soms appear, this being the softest portion of the plant 
at this period. Later on adults in resting period are found 
in seed pods or secreted around the base of the plants. 
There are two generations in the summer ; the adult individ- 
uals appearing first in the spring, then again in the sum- 
mer, and again in the autumn. They do not do any great 
damage to the leaves, although they feed upon this plant 
exclusively. 

Another species, Phloeothrips nigra, occurs in clover 
bloom. It is a black species and evidently restricted to 
clover. The larva is bright red and often found during 
the winter. They feed on part of the clover bloom and so 
far as it has any effect, is destructive to the clover. One 
, species is credited with feeding upon the grape Phylloxera. 
If it does this it is an exception to the usual food habit of 
the family. It possibly may feed ordinarily upon the tissue 
of the gall and exceptionally on the plant lice that occur 
within the gall. 

The group as a whole is to be considered as herbivorous 
rather than carnivorous, and injurious when occurring on 
useful plants. 



CHAPTER V. 
ORDER HEMIPTERA. 

The Hemiptera constitutes one of the large orders of 
insects and includes some of the very important economic 
species, and some of the very striking specializations in 
insect life history including extremes in different kinds of 
environment, life habit, and one of the most striking extremes 
in the matter of reproduction and development. 

The essential character of the order is found in the devel- 
opment of the mouth parts, there being also other distinct 
differences in the matter of wing structure and some other 
parts of the body. The mouth parts are adapted for suction 
in the larval as well as the adult stages. This represents a 
more radical change of these parts than when the mouth 
parts are different in different stages. The modification 
in the mouth parts consists in the change of the mandibles 
and maxillae into bristles or setae which serve to puncture 
the tissues of the plants upon which the insects feed by 
pumping out the juices. The labrum (epipharynx of some 
authors) is present as a rather aborted structure ; the labium 
is modified into a sheath for the bristles or setse and is usually 
three- or four-jointed. These segments are fitted together 
to form a sheath or tubular or furrowed organ within which 
the bristles or setse play back and forth as they are driven 
into the tissues which constitute the food of the insects. 
Within the group there are differences in wing structure 
which enable us to separate the group into two very distinct 
suborders, and in some cases three are recognized, the third 
including only parasitic forms. 

The two main suborders are the Homoptera and the 
Heteroptera, the first including those forms which have 

(93) 



94 



ORDER IIEMIPTERA 



membranous or opaque, but homogeneous wings; the seeond 
having the front wings thiekened at the base and membranous 
at the apical portion. The Heteroptera are often given first 
as if more primitive, but the Homoptera appear to have the 
most fujidamentally primitive character. The venation 
of the wings and the position of the head particularly seem 
of more primitive character than in the Heteroptera. 

The third group, Parasita, includes the suctorial lice; 
the wings are lost, beak is single-jointed, and setse are very 
much elongated and tubular. They are restricted to the 
w^arm-blooded vertebrates, mammals. 




Fig. 52. — The periodical cicada {Tihiceyi septendecetn) : a, adult; b, 
same, side view; c, shed pupal skin. Natural size. (After Mailatt, Bur. 
Ent., U. S. Dept. Ag.) 



The Homoptera are divided into two divisions, Auch- 
enorhynchi and Sternorhynchi. In the first group the beak 
is free, not attached to the sternum, and may be moved 
readily from the head as its base. In the second group it 
is fused into the sternum and the base connected with the 
head at about right angles to the sternum. This latter is 
a specialized condition and must be derived from the simpler 
condition where the beak is free. 

In the Auchenorhynchi the Cicadida? are one of the most 
prominent families, which is apparently rather generalized 
in its features. They show specialization in their life his- 



ORDER HEMIPTERA 



95 



tory. The most common species, or, for the Homoptera, one 
of the most widely known, is the seventeen-year cicada, 
which is especially remarkable on account of its long life. 
The seventeen-year cycle is certainly known and well estab- 
lished by observation. The adults appear at these periodical 
intervals in the latter part of June and they are apparent 




Fig. 53. — Tibicen septendecem: adults on two-year-old apple tree. 
(Photo from Ohio Exp. Sta.) 



during this stage when they feed very slightly on vegetation, 
mate and deposit their eggs during a period of four or five 
weeks, though they are seen in great abundance for a period 
of only a few days. They are noticeable from their size 
and from the very loud note that is produced by the males. 
The song is a long-drawn-out sort of screech and is produced 



96 



ORDER HEMIPTERA 



by an organ located in the base of the abdomen, covered 
by the wings when folded and slightly covered from below 
by an operculum. The structure of the drum is somewhat 
flattened and inside is a cluster of muscles attached to the 




Fig. 54. — Tibicen scplcndtcem: adults 

(Photo from Ohio Exp. Sta.) 



apple tree. 



abdominal wall. Their contraction serves to draw this 
membrane in, after which it immediately resumes its former 
position and when repeated rapidly this causes a vibration, 
producing a whirring or buzzing note which varies in inten- 
sity with the rapidity of the vibrations. Its purpose has 



ORDER HEMIPTERA 



97 



been interpreted as that of a mating call, but no auditory 
organ has been described. The females deposit eggs in 
twigs of trees, puncturing the trees with little furrows, which 
result in splitting the bark, and the twigs often die. The 




Fig. 55. — Tibicen septendecem: twigs broken from egg deposition. 
(Photo from Ohio Exp. Sta.) 



eggs hatch five or six weeks after their deposition. The 
larvae drop from the twigs and pass into the ground and from 
that time on for almost the next seventeen years are out of 
sight and are growing gradually, moulting occasionally, 

7 



98 ORDER IIKMJPTERA 

l)r()l)iil)ly once ii year tit letist. TJiey feed for the most ])art 
on tlie roots of trees and shrubs and woody plants occurring 
in their location. WJien trees are cut away after the eggs 
are depositcMl, some of the nympJis douhtless fail to develop, 
hut there are some that become mature. 

TJie uniformity' in tlieir appearance may be accounted 
for by the fact that those that did not come out at a definite 
time had little chance of breeding and re])r()ducing. They 
occur throughout the eastern United States and the seven- 
teen-year form mostly to the north of the latitude of the 
Ohio river. To the south of that latitude there is a thirteen- 
year form. They do not occur over the whole area of the 
country in which they may be considered as native, there 
being portions where they do not occur at all, other places 
where they occur twice in seventeen years, and still other 
places where tht^v occur three times in seventeen years. 
They may be descendants of a generalized mass of cicadas 
\vith a shorter life period. Just why they have been retarded 
is another problem. Their subterranean habit and conse- 
quent slow growth might serve to prolong their life. 

The dog-day cicada w^hich appears commonly in August, 
lays its eggs in twigs of various trees, but the growth of 
the nymph is much more rapid. The injury is the same as 
in the seventeen-year cicada. The attacks of the adults 
in young orchards are sometimes serious. 

After the Cicadichv the Membracidae are perhaps the 
most generalized, though they present a specialized struct- 
ure of the thorax. They are called treehoppers, the majority 
inhabiting trees and shrubs, a few only occurring on her- 
baceous i)lants. The specialization of the thorax is shown 
in various ways. The prothorax is the greatest part of the 
body visible from above. There are many variations and 
these result in a great many forms of mimicry and protec- 
tive resemblance. Some forms have the posterior ])art of 
the prothorax broken up into globular pieces simulating the 
body of an ant. In some cases there are three large knobs 
which hang out from the central part and probably resemble 
parts of the tree on which it occurs. They take on the 



ORDER HEMIPTERA 



99 



greatest variety of forms, many very grotesque. The group 
is large and includes many species. There are probably 
fifty species in the latitude of the Northern States. 

One of the most common is the buffalo treehopper, 
Ceresa hubalu.s, which abounds on thorn, apple and maple 
trees and is frequently found on other vegetation. It is 
of an apple-green color, with faint, light yellow mottlings 




Fig. 56. — Buffalo treehopper: a, female; b, enlargement of foot; 
c, antenna; d, wing; /, g, ovipositor; h, ?, terminal segment of male abdomen; 



e, terminal segment male taurina. 
Ag.) 



(After Marlatt, Bur. Ent., U. S. Dept. 



or specks, distributed over the pronotum. The pronotum 
itself stands out in two prominent horns. It extends back 
in a very pronounced spine. The eyes are quite prominent 
and stand out at the sides of the head. There are four species 
closely related, but this one is the most abundant. Its life 
history is quite characteristic for the group. They are 
single-brooded and the winter is passed in the egg stage; 
the eggs are deposited in twigs of various trees in little slits 



lUU 



ORDER HEMIPTERA 



of the bark, with sHghtly crescent-shaped scars, and eggs 
are arranged in parallel rows, causing damage to the trees. 
The young hatch in the spring and early summer and as 
hatched they are quite grotesque. The body is shaped 
something like that of an adult, but along the dorsal line there 
is a series of sharp spines, the divisions of the body are fairly 
well marked and the divisions of the abdomen are distinct. 




Fig. 57. — Ceresa bubalus. Twig of apple showing: a, female at work; 
b, recent egg puncture; c, bark reversed with eggs in position, slightly 
enlarged; d, single row of eggs still more enlarged; c, wounds of two or 
three years' standing on older limbs. (After Marlatt.) 

There is no such expansion of the prothorax as in the adult. 
They moult several times and with the aquisition of the wdngs 
the pronotum becomes fully expanded. The moults occur 
mainly in June and July and the adults appear usually in 
the latter part of July. Deposition of eggs occurs rather 
early in the fall. A considerable part of the year is spent 
in the egg stage. Injury is caused by pumping the sap and 



FAMILY FULGORIDjE 



101 



is limited to a rather short period, but the injury caused 
by puncturing the twigs for egg deposition does not fully 
appear for a year or two after the eggs are deposited. The 
scars and distorted growth of the twig may seriously dis- 
figure and weaken the branch. It is rather difficult to apply 
any distinct remedy because they occur on so many different 
kinds of plants. Cutting off the infected twigs would be 
possible but hardly practicable on any large scale. The 





h 

Fig. 58 Fig. 59 

Figs, 58 and 59. — Ormeriis pruinosa Say: at right, a and b, adults; at 

left, a, eggs, much enlarged; b, eggs in bark; c, twig with eggs. (After 
Lugger.) 



application of kerosene emulsion would be effective at the 
same time that other forms are developing, thus killing off 
more than one species at one time. 

Family Fulgoridse. — The family Fidgoridoe presents ex- 
treme specialization in some directions. These occur in the 
head region instead of the pro thoracic region. In one 
of the most extreme forms the head is spread out into a 
great peanut-like structure, and in one form there is an 



102 



ORDER HEMIPTERA 



appearance of a large spot on this head portion, and in one 
species there is stated to be phosphorescence. Tlie tliorax, 
wings and abdomen have for the most part normal character 
or some variation in the wings. It is an enormous family, 
especially represented in the tropics. There are few strik- 
ing members of the group represented in northern latitudes. 
A good many of the forms are inconspicuous. A few special 
forms representative of the group may be mentioned. 




Fig. 60. — Fulgorid. (Original, from drawing by Miss Edith Hyde.) 



Otioceras. — Otioceras is as elegant a little insect as can 
be found in any group of insects. They appear very much 
like delicate little moths. The head is drawn out into a 
ploW' share-shaped form. The eyes are prominent and the 
antennae very peculiar, with little flabella-like appendages. 
The eyes stand out at the sides of the head, the wings run 
back in a moth-like form and are quite delicately veined 
and marked. These occur mainly on hickories or closely 



FAMILY FULGORID^ 103 

related trees, in August and September or October. They 
may be obtained by beating the trees over an umbrella with 
a stick. The genus includes six or eight common species. 
They are quite similar in general appearance. 

Delphacidae. — The Delphacidse are characterized by the 
presence of a large, movable spur on the end of the tibia, 
and tibia and tarsal joint run out with spines. A specialized 
appendage for attachment to twigs, stems of grass, etc., 
enables the insects to jump more readily. This is a charac- 
teristic structure for this group. These hoppers occur 
abundantly in low vegetation, especially on grasses and 
some species are abundant enough to be detrimental, as for 
instance, the corn Delphacid (Dicranotroins maidis), and the 
sugar-cane hopper, which has been extremely destructive 
in the sugar plantations of the Hawaiian Islands. Our 
species occur sometimes in blue-grass meadows, and do some 
damage. They are minute, varying in size from one and 
a half to two millimeters, to four or five millimeters in length. 
They present a great variety of modification in wing develop- 
ment. Some are dimorphic. There are some in which the 
hind pair of wings are wanting or not full-sized, some in 
which front wings are reduced entirely or to mere rudiments. 
This occurs first in the females, but also in some species in 
the males. The greatest amount of reduction appears to 
occur in those which live where food supply is abundant 
and flight becomes unnecessary. There may be a summer 
generation without wings and a fall generation with wings. 
One other interesting feature is the fact that they are para- 
sitized in a peculiar manner. Certain Hymenopterus para- 
sites deposit eggs on the bodies of these and larvse are pro- 
duced in a sort of sack extruded between the segments of 
the abdomen, and within this sac the larvae develop. These 
parasites may have some value in reducing the number of 
the hoppers. 

The eggs are deposited in the leaf or stem of grasses, etc., 
and the larvae hatch from these and feed on the plant 
attacked. The stages of development are gradual and there 
are one or two broods annually for the most of the species. 



104 



ORDER HEMIPTERA 



Some of the forms have adult hibernation and others egg 
hibernation. 

Family Cercopidse. — The CercopidcB is a family that has 
few economic species. They difi'er from the Fulgorida? in 
having the head and thorax rather normal in shape, first 
pair of wings usually thickened opaque and venation not 
very consi)icuous. The thorax is well developed, the tibia 
terminates in a prominent crown of spines and no spines 




Fig. 61. — Aphrophora A-notata Say: a, from above; b, from side. 
(From Lugger, Minn. Ann. Rept. 6.) 



on the sides of the tibia. These include the little frog hop- 
pers or "spittle insects." The larvse suck the juices of the 
plants on which they occur and pump out more juice than 
they have use for and extrude it from the body in fluid form 
and set air free within this juice, making the frothy mass 
which covers the entire body of the larvse. These masses 
are found hanging on the stems of plants very frequently 
during the summer. After they have passed through the 



SUPERFAMILY JASSOIDEA 105 

larval and pupal stages they do not secrete any such frothy 
masses. 

Superfamily Jassoidea. — The superfamily Jassoidea in- 
cludes several subdivisions of considerable importance. They 
abound particularly on low vegetation, and some are grass 
feeding, others tree inhabiting. They differ from the Ful- 
goridse in the more specialized and compact head and 
thoracic region and in the more distinctive character of the 
hind tibia which is more prismatic in form and wdth two 
rows of spines and without any circle of spines at the tip. 
The subdivisions are separated by means of the venation 
of the wings, and by the head parts. There are four fairly 
distinct families. 

The life histories are somewhat complex. Some species 
have a single brood each year, others two, others apparently 
three. Some hibernate as adults, many as eggs, some 
apparently in partially developed nymphal stages. Some 
of the striking examples are the grass leafhoppers, forms 
that live continually in the grass and suck the sap, causing 
a considerable decrease in the crop, reducing quantity and 
quality of the nutritive contents of the grass leaves. In 
some the individuals are extremely abundant, one to two 
millions to the acre. 

The life histories are much the same throughout the group, 
but not many have been worked out in detail. The group 
stands as one of the most specialized of the Homoptera 
that have the primitive condition of the mouth parts. 

The term vertex is used for the upper surface of the 
head between the eyes and extending to the front border, 
which may merge gradually into the front or the face. The 
frons, or front, is the part of the face lying between the 
sutures and extending down nearly to the lower border. 
At the sides of this are portions next the eyes, which are 
termed the cheek, and below the front a part called clypeus, 
at the sides of which are the lorse. The central part of the 
body which bears the wings and legs is termed the thorax, 
and the upper portion of the first segment is known as the 
pronotum. The front wings are termed elytra and are 



106 



ORDER HEMIPTERA 



usually thicker and stronger than the hind pair, which are 
concealed beneath the front ones when at rest. The abdo- 




FiG. 62. — Explanation of terms, from drawing of Athysanus obtutus: a, 
female from beneath; b, from side; c, from above; d, female genitalia; 
e, male genitalia; /, larva or nymph; g, eggs, showing developing larvae; 
h, egg, enlarged; i, eggs in position beneath sheath of grass stem. Structural 
details: ac, apical cells; a.ac, anteapical cells; cL, clavus; clyp., clypeus; cox., 
coxa; fr., front; fern., femus; lora, lora; ov., ovipositor; plate, plate; pr., 
prothorax; py. ((f), ry. (P), pygofer; tar., tarsus; lib., tibia; v., vertex; 
vs., terminal ventral segment; valve, valve. All enlarged. (After Osborn 
and Ball.) 



men may be entirely hidden above by the wings, but in 
short-winged forms is more or less exposed. The parts of 
greatest importance on the abdomen for purposes of descrip- 



SUPERFAMILY JASSOIDEA 



107 



tion are the terminal segments, including the genitalia. In 
the female the last ventral segment is frequently of a par- 
ticular shape or structure for different species and in many 
groups is of the greatest service for description. It is fol- 
lowed by the sheaths of the ovipositor, this latter being a 
narrow, saw-like pair of blades, extending to the tip, some- 
times considerably beyond the tip of the sheaths. The 
males have a terminal segment beneath a modified segment, 
called the valve, which is followed by two movable pieces 
called plates. Above these, forming the sides of the last 




^ . J (\ A« U \ .\ o\t a\» . 



Fig, 63. — The clover leaf hopper (Agallia sanguinolenta) : a, adult; h, 
nymph, side view; c, nymph, dorsal view; d, face; e, elytron; /, female 
genitalia; g, male genitalia. All enlarged. (After Oshorn and Ball.) 



segment, are the pygofers. A ready understanding of these 
various parts will be helped by a study of the accompanying 
figure, in which they are located and named. For the 
different stages of insects the usual terms egg, larva, or 
nymph, pupa, and adult are used, as these are sufficiently 
definite in indicating the steps of development from the 
egg to the mature form. 

Bythoscopidse. — The Bythoscopidce include forms which 
are for the most part found upon trees or woody plants, 
sometimes in great abundance and which doubtless occasion 
considerable injury, although the effect in any particular 



108 



ORDER HEMIPTERA 



case may not be very apparent. The common species 
affect willows. 

Idiocerus alternatus lays eggs in the bark and passes 
through two generations each year. 




Fig. 64. — Glassy- winged sharpshooter: a, adult?, seen from above; b, 
side view; c, venation of forewing, enlarged; d, antennse; e, section of 
hind tibia; /, 9 genitaha, more enlarged; g, serration of ovipositor, still 
more enlarged. (From Howard, Bur. Ent., U. S. Dept. Ag.) 

Clover Leafhopper. — Another form of considerable eco- 
nomic importance, the clover leafhopper, is a very common 
pest of clover and alfalfa and has been noted as troublesome 
in sugar-beet fields. 

Family Tettigoniellidse. — The family Tettigoniellidoe in- 
cludes an enormous number of species occurring in the 
tropics and a considerable number of common forms through- 



FAMILY TETTIGONIELLID^ 



109 



out the temperate regions, among them a particular species 
known as the sharpshooter, Oncometopia undata, which 
discharges droplets of liquid, so that when the insects are 
abundant, the tree in which they occur may shed consider- 




FiG. Q5.—Dr(BCulacephala mollipes: a, adult from above; b, face, much 
enlarged; c, vertex and pronotum d"; d, female genitalia; e, male geni- 
talia; /, wing; g, h, nymphs. All enlarged. (After Osborn, Bur. Ent., 
Bull.' 108.) 



able liquid, and this leads to the name "weeping tree." 
The glassy-winged sharpshooter, figured here, has a similar 

habit. 

Tenderfoot Leafhopper.— A species which is very abundant 
in grass lands is the tenderfoot leafhopper, Dmculaceyhala 



no 



ORDER HEMIRTERA 



molliyes. This is li^ht ^rass-^reeii in color, quite slender, 
has a very sharply pointed liead, and is very well ])r()tected 
on the blades of grass both by its color and form. It occurs 
on a great variety of grass plants and is known all the way 




Fig. 66. — The shovel-nosed leafhopper (Dorycephalus platyrhynchus: a, 
female; b, male; c, face; d, female genitaUa; e, male genitalia; /, eggs in 
grass stem; g, eggs; h, egg, more enlarged and showing developing nymph; 
i, j, k, I, different stages of growth of nymph. All enlarged. (After 
Osborn and Ball.) 



from Canada to Central America. The nymphs have 
fairly well-marked longitudinal stripes arranged as shown 
in the figure, but are much less commonly observed than 
the adults. 



FAMILY JASSIDM 



111 



Family Jassidse. — The family Jassidoe, including the forms 
which have the ocelli located in the margin of the head be- 
tween the vertex and front, is very largely represented in 
temperate regions and many of the species affect important 
cultivated crops. 




Fig. 67. — The inimical leafhopper (Deltocephalus inimicus): a, adult; 
b, face; c, vertex and pronotum; d, female genitalia; e, male genitalia; 
/, elytra; g, nymph. All enlarged. (After Osborn and Ball.) 



Shovel-nosed Leafhopper { Dorycephalus platyrhynchus) . — 
The shovel-nosed leafhopper is a rather large species with 
an enormous prolonged head and is found upon the wild 
oat, Elymus canadensis. The eggs are laid beneath leaf 
sheaths, a considerable number in a compact row and the 



112 



ORDER HEMIPTERA 



nymphs on hatching begin feeding at once upon the grass. 
The adult females have short wings and do not jump or fly 
rapidly. 

Inimical Leafhopper { Deltocephalus inimicus). — The in- 
imical leafhopper is perhaps the most abundant species 
throughout the northern United States where blue grass 
is a common pasture grass. While abundant and almost 




Fig. 68. — The inimical leafhopper (Deltoccphalus inimicus) : nymphal 
stages: a, newly hatched; h, c, d, later stages, the details of tarsal appen- 
dages shown below. All enlarged. (After Osborn, Bur. Ent., Bull. 108.) 



universal in blue grass, it may also be found upon other 
species of grass and also in wheat and alfalfa. This species 
is so abundant and wide-spread that it is almost impossible 
to sweep a patch of blue grass in any locality from Maine 
to Washington, and south to northern Tennessee, without 
finding it in abundance. The nymphs pass through five 
distinct stages with differences in the shape of the head and 
development of wing pads and an increase in the number 



FAMILY JASSID^ 



113 



of minute appendages on the first tarsal segment, as shown 
in the figure. 

The destructive leafhopper {Athysanus exitiosus), was 
first noticed as a pest in grain fields in the Southern States, 




Fig. 69. — The destructive leafhopper (Athysanus exitiosus) : a, adult 
female, dorsal view; b, head and pronotum of male; c, face of female; d, 
female genitalia; e, male genitalia; /, wing; g, eggs dissected from female; 
h, i, j, three stages of nymphal growth. All enlarged. (After Osborn, 
Bur. Ent., Bull. 108.) 

but is now known to be distributed throughout the larger 
portion of the United States, which likely is the result of a 
dispersal from the southern localities with possible intro- 
8 



II I 



OHhI'lh' IlI'lMII'TiaiA 



(lil(li(Hi IVom (he WVsJ liidirs oi* Mexico in sonic iiol (jisljmt 
|)ci"io<i. 

Six-spotted Leafhopper. Tlic si\-s|)ollc(l icjil'lioppcr occiii-s 
ill iil)iiii(laiicc t lii*oiif;lioii( (lie ('oiiiili-y .mikI is ;ilso w (-oiiiiiioii 
species ill l^'nrope. Wliellicr i(s coimiioii distrihiitioii is due 
to ori<;iii!il cxlciil of I lie species, (H- wliellicr tlic s|)ecies lias 
been iiilrodiiccd iiilo America in niodeni iinies, is inip(>ssil)le 
to say. Il dc\ clops rallicr rapidly and appaiciilly |)a.sses 
tliron^li 1\V(> or lliree ;;'eiiera(ioiis at least in iKH-llicrn locali- 
ties, and |)ossil)ly three to (i\(' in the more southern States. 
It is es|)ecially iiiiinions in oat fields. 






I''l<i. 70. Tlic .six-M|M.|lc(l l.>;iriii)|)i)ci- {('inidiilit {\iii>l<ilii): </. iidiiK ; 
/*, fiic(«; (', \\\\\n.; <l. liMii.'ilc >!:»Mii(jili!i; r, mjiU^ ^(Miilnliii; /. iivmpli. All 
tMiliii-k'cd. (Allvr OslH.rn. Hull. lOS, liiir. lOiit., U. S. Drpl. Ak.) 



Typhlocyhida' inchides a <;'rou|) ol' mimite forms most of 
which are found on trees or woody plants, hut certain ones 
occur on i;fains or i;rasses. The most familiar and destruc- 
ti\c forms are (he «;rou|) of leafho|)pers which cause witli(>r- 
iiii;- and whitcnin;;- of n-r;,|)e-\in(>s in the midsummer and 
autumn. Tuphlonilxi conir.s includes S(>\('ral xarictics, all 
of which are d(»s(ruc(i\(' (o i;rai)es. lli(> nym|)hal s(a,i;'es 
Ix'iii^^ found usually (Ui (he under side of ihc lca\(>s. and the 
elVeet of their |)unc(urinj;- shows in miniilc while sjxyls on 
the u])])er surface of the leaves. 



FAMILY I'SYLLID.K 



iir, 



Apple Leafhopper {Empnasca mall). T\\v ',\\)\)\(' l(';il"lj()i)i)('r, 
juiolluM- very destructive form, jdVccts ;i|)i)I(' Jiiid other 
IVuit trees. Oeeasioiuilly it is destriK live to ;dl'iill';i, cow 
|)e;is, i)otMtoes Miid Ix'Miis. 




Fio. 71.— Pesir-ireo p.syllii: .idiilt fctiiMlc iwitiinil Hi/>(! indif!il,(!(l l»y Hide 
lino. (From Miuhilt, l)\v. Kui., 11 S. l)v])\. An,.) 

Tlie Sfrrnorhi/nrlii include those I Ioinoj)ter}i thjit iuive 
the beak fused jnto tlie st(;riunn. The ^n-oup contains some 
reriKirkahly specialized forms of insects an(l there are four 
distinct famihes, closely linked together by connecting 
forms. 

Psyllidae. The l*sj/lll(l(i; seem closely relate<l to tJic 
cicadas. TJie shai)e of tlie body and licad is like that in the 



116 



ORDER HEMIPTERA 



cicadas, wings specialized, and they differ in the beak 
being fused into the sternum. They are descended from a 
generalized insect like the cicada in character. The prin- 
cipal line of specialization has been in the fusion of the beak 
and sternum. It stands out at almost right angles to the 
prothorax, between the front legs. 

All of the species are quite small. Some feed directly on 
the surface of plants. Others present a distinctly specialized 
food habit, producing galls on various trees, expecially 
on the hackberry. 




Fig. 72. — Pear-tree psylla: n, egg; h, larva, but greatly enlarged. 
(From Marlatt, Div. Ent., U. S. Dept. Ag.) 



A common and destructive species in the Eastern States 
is the pear psylla which causes serious loss in pear orchards. 

One of the most common is PachypsyUa celtidis-mamma. 
The larvae are found in cavities in the galls; the galls are 
formed by the deposition of eggs on the surface of the leaves 
and the stimulation of the leaf celh. The life-cycle must 
be adapted to the growth of the leaf on which it occurs. 
In the gall, when dried up in the fall, are found either adults 
or mature nymphs. The adults usually emerge and secrete 
themselves in fallen leaves, etc. The adults appear in the 
spring at about the time that the hackberry leaves are ex- 
panding and deposit eggs on the surface of the leaves, and 



FAMILY APHIDIDM 



117 



during the rapid growing period of the leaf these galls are 
developed and the larvae are growing within them. There 
is a single generation during the year. This is the plan of 
development for practically all of these psyllid galls. A 
number of different kinds occur on hackberry trees. They 
are readily identified by the character of the galls produced 
on the trees. Most species are located on the leaves, but 
some species form a structure on the twig by a modification 




Fig. 73.- 



-Pear-tree psylla: nymph greatly enlarged. 
Ent., U. S. Dept. Ag.) 



(From Marlatt, Div. 



of the bud. There is a distinct specialization in the matter 
of food supply which characterizes a large part of the family 
Psyllidse. Stimulation of the plant tissues is produced by 
the action of the larvae in puncturing the cells. 

Family Aphididse. — This family is specialized particu- 
larly with reference to the mode of reproduction. It agrees 
with other forms of the Sternorhynchi in having the beak 
apparently fused with the prosternum, so that the beak 
appears to arise from the sternum. There is a reduction of 



118 ORDER HEMIPTERA 

the venation in some genera. The forms witli the most 
numerous \eins are the more primitive and tlie fewer-veined 
forms must be regarded as speeialized. 

The nectaries, or so-called "honey tubes" or "cornicles," 
are structures peculiar to Aphididiie, located on the hinder 
l^art of the abdomen. Fluids may exude from their tii)s and 
much difference of ojiinion has existed as to their functions. 
Some think that the fluids are used as a means of defense. 
It is now generally accepted that the "honey dew" emitted 
by plant lice is discharged from the anal opening, and con- 
sists of slightly modified sap from the plant to which the 
aphid is attached. It is sweet and may form some sugar on 
evaporation and is much sought by ants and some other 
insects. 

Aphids are characterized by the appearance of several 
successive generations which are devoid of wings and closely 
confined to their host plant. Reproduction is in large 
measure parthenogenetic, many generations occurring with- 
out the appearance of the sexual forms. A rapid rate of 
reproduction is provided for; sometimes as many as ten or 
twelve generations in a season. It has been estimated that, 
starting with one stem-mother in the spring, her progeny 
during the season, if not curtailed, would amount to bil- 
lions or trillions of individuals, sufficient to overrun the 
world or to equal in bulk of organic matter the population 
of China. The agamic eggs are termed "pseudova," and 
are often developed and hatched before being extruded 
(ovoviviparous). 

No general statement can be made which will properly 
cover the life history and development of all species, but in 
general, and in the temperate latitudes particularly, hiber- 
nation takes place in the egg stage. As the usual thing these 
eggs are fertilized and occur on the plant which was the last 
host of the species in the autumn. In the spring these eggs 
hatch into stem-mothers, which are asexual individuals and 
for which there is no corresponding male. They do not 
require fertilization and they produce either eggs or living 
young. The young produced are ordinarily wingless when 



FAMILY APHIDID^ 119 

they mature and as many as two or three generations of 
these agamic apterous forms may be produced. Next, 
alate (winged) forms are produced, usually asexual, to pro- 
vide for a migration of the species to another host plant. 
As a general thing these winged migrants usually produce 
mainly wingless, agamic forms. In the autumn a winged 
form appears (usually asexual) which permits the return of 
the species to its original host. Frequently with aphids 
having alternate food plants the spring and autumn host 
plants are perennials — woody or shrubby plants, the sum- 
mer host plant an annual. A number of cases, however, of 
alternation between woody plants are known. An example 
of the former is seen in the case of an apple-plant louse, 
Siphocoryne avenoB, which winters over in the egg stage 
on apple trees, the spring forms occur for two or three 
generations on apple and then apparently disappear; in 
reality they migrate to wheat and breed on it during the 
summer. With the ripening of the wheat the lice leave 
and return to the apple. In the case of the hop-plant louse, 
Phorodon huniuli, the spring and fall forms occur on wild 
plum and the midsummer forms by migration on the hop 
plants, which accounts for their very sudden appearance 
and in such large numbers in the hop vineyards in summer. 

The return migration in autumn to the original host 
plant may be followed by two or three generations of 
asexual, agamic individuals. After that, a short time prior 
to the end of the breeding season, the sexual forms are 
produced. The appearance of the sexual forms may possibly 
be induced (or precipitated) by the ripening and hardening 
of the plant tissue of the host. The same factor, in case of 
the summer annual host plant, may determine the time of 
the return migration to the spring and autumn host plant. 

The sexual forms are often wingless and very small and 
are less dependent upon the host plant for food than are 
the other forms. Aher mating, the female produces one or 
two eggs or at least a very small number of eggs and these 
eggs are usually attached to permanent parts of the tree, 
seldom to leaves or stems. These eggs are usually hard, 



120 ORDER IIEMIPTERA 

tough, iisiiall>' black, polished and resistant to the weather. 
They are sometimes so abundant on the surface of apple 
twigs as to give the latter a shiny appearance. The follow- 
ing spring these eggs hatch into the stem-mothers. 

Control. — Control measures in general resolve themselves 
into destruction of the over-wintering eggs, prompt appli- 
cation of insecticides in early spring, and such measures as 
are applicable through recognition of the alternate-host 
habit. The hop-plant louse control depends on elimination 
of the alternate host, wild plum. 

To the general and usual method of hibernation in the 
egg stage there are exceptions. Thus the corn-root louse 
is carried over the winter on roots in the ground by its 
attendant ant. Through this dependence on the ant being 
long-continued this species has evidently become independent 
of the egg-depositing habit or produces eggs only at intervals. 

Outbreaks of plant lice are often very destructive and 
and are more or less evanescent. The lice appear suddenly, 
to all appearances, and often seem to disappear as quickly. 
The aphids are victims to a multitude of predaceous enemies 
and Hymenopterous parasites, are susceptible to weather 
conditions, such as rains, low temperatures, etc. 

Migrations in spring are usually for short distances, rarely 
over a mile or so, or until a suitable summer host is found. 
Fall migrations, involving many more individuals, are much 
more general and the insects more widely scattered, and are 
carried along by winds and may be quite widely distributed 
at that time. Among the important species are the corn- 
root louse, hop-plant louse, cherry aphis, apple aphis, etc. 

An intimate relationship exists between the plant lice and 
ants, this being sometimes carried so far as to make the 
insects mutually dependent on each other. Such is the case 
with the corn-root louse and its attendant ant, in which the 
ant depends for its food upon the honey dew of the aphid 
and the latter in turn depends upon the ant for its trans- 
portation from one root to another. In this and other cases 
plant lice are definitely protected by the ants or carried over 
from season to season in order that the ants may get the 



FAMILY APHIDIDyE 



121 



benefit of the honey dew which is extruded from the anal 
opening. There is no very definite glandular structure con- 
nected with the nectar tubes or cornicles but a liquid does 
come from them and its function is interpreted in various 
ways, one being that it serves the insect in defence against 
predaceous or parasitic enemies. 



==^ 




Fig. 74. — Pea aphis {Macrosiphum pisi): a, winged female; b, same 
from side, with wings folded in natural position, as when feeding; c, apterous 
female; d, nymph in last stage; e, third joint of antenna of winged form; 
a and d, much enlarged; e, more highly magnified. (From Chittenden, 
Div. Ent., U. S. Dept. Ag.) 



The classification of the Aphididse is based largely on the 
structure of the winged forms, and it is very desirable that 
the winged form of a species be obtained in attempting its 
identification. 

Other characters of special value are found in the antennae, 



122 



ORDER HEMIPTERA 



relative length and nnmber of joints, location of sensoria 
in the honey tubes or nectaries, and the anal style. 




FiCx. 75. — Spring grain aphis (Toxoptera graminum) : male, greatly 
enlarged. (From Webster, Div. Ent., U. S. Dept. Ag.) 

Pea Aphis. — The pea aphis is a species which occasionally 
multiples to an enormous extent and causes heavy losses 




Fig. 76. — Spring grain aphis (Toxoptera graminum): egg-laying female 
with eggs in body, greatly enlarged. (From Webster, Div. Ent., U. S. 
Dep. Ag.) 

in the pea crop. Another very destructive species at times 
is the one affecting melons. 



FAMILY APHIDID.^ 123 

Spring Grain Aphis. — The spring grain aphis or ''green 
bug" {Toxoptera graminum) has attracted a great deal of 
attention, especially in the Southwestern wheat growing 
sections; in Texas, Oklahoma, and Kansas where it has 
caused severe injury to the wheat crop. It is an introduced 
species and seems especially adapted to the Southern wheat 
districts. It is extensively preyed upon by a small parasite 




Fig. 77. — The spring grain aphis {Toxoptera graminiwi) : winged migrant, 
much enlarged; above, antenna of same highly magnified. (After Pergande, 
Div. Ent., U. S. Dept. Ag.) 

(Lysiphehus) , and this parasite assists in a large degree in 
keeping it in check. 

Corn-leaf Aphis. — The corn-leaf aphis {Aphis maidis) is 
injurious to the corn plant and occasionally appears in 
destructive numbers but ordinarily is less injurious than the 
related corn-root aphis. 

Corn-root Aphis {Aphis maidi-radicis) . — The corn-root 
aphis is a special pest of cornfields and a larger part of its 
attack is confined to this crop. It is a light green or bluish- 



124 



ORDER HEMIPTERA 



green, affected evidently by its subterranean ha})it. The 
species is notable on account of its dependence on the ant 
for its transfer from one food plant to another. 




Fig. 78. — The corn-leaf aphis (Aphis maidis) : winged female. Much 
enlarged. (After Webster, Div. Ent., U. S. Dept. Ag.) 




Fig. 79. — The corn-leaf aphis (Aphis maidis): wingless female. Much 
enlarged. (After Webster, Div. Ent., U. S. Dept. Ag.) 



The eggs of this species are cared for by the ant through 
the winter time. When hatched the young are transferred 
to suitable plant roots, often to the roots of weeds in the 



FAMILY APHIDIDJ^ 



125 




Fig. 80. — The corn-root aphis (Aphis maidi-radicis) : winged female. 
Much enlarged. (Webster, Div. Ent., U. S. Dept. Ag.) 





Fig. 81 Fig. 82 

Fig. 81. — The corn-root aphis (Aphis maidi-radicis): wingless female. 
Much enlarged. (Webster, Div. Ent., U. S. Dept. Ag.) 
Fig. 82. — Aphis on apple. (Photo from Ohio Exp. Sta.) 



120 



ORDER HEMIPTERA 



fields, upon which the hce maintain themselves until corn 
plants are available 

This species aj)pears to become so comj)letely adapted 
for underground life and the association with ants that it 
does not necessitate producing any winged generation for 
distribution or for alternation with another food plant. 

On account, of this relation to ants, one of the measures 
of control is to plow and harrow the ground thoroughly 




Fig. 83. — Woolly aphis {Schizoneura lanigera): a, agamic female; b, 
larval louse; c, pupa; d, winged female with enlarged antenna above; 
all greatly enlarged and with waxy excretion removed. (From Marlatt, 
Div. Ent., U. S. Dept. Ag.) 



in order to break up the nests of the ants. This method 
adopted in the autumn together with a wider cultivation 
and destruction of weeds in the fields in spring will assist 
in keeping the pest in check. Perhaps the most important 
measure is a rotation of crops so that corn will not be culti- 
vated for a number of years in succession on the same ground. 
Woolly Apple Aphis {Sckizorievra lanigera). — The woolly 
apple aphis is a very destructive species, its injury for the 



FAMILY APHIDID^ 



127 



most part being noted upon apple trees and is credited with 
attacks both on the roots and trunks of some trees, Hmbs 
or larger twigs near the ground. It is covered with a white 
cottony substance and this tends to shed water. On the 




Fig. 84. — Woolly aphis (Schizoneura lanigera) : a, root of young tree 
illustrating deformation; h, section of root with aphides clustered over 
it; c, root louse, female — a and h, natural size; c. much enlarged. (From 
Marlatt, Div. Ent., Circ. 20, 2d series, U. S. Dept. Ag.) 



roots it produces large knotty swellings and these injuries 
cause serious effects upon the tree. Usually these insects 
are observed in a wingless form but in the autumn some of 
the individuals become winged and migrate to the elm, 



128 



ORDER HEMIPTERA 



where in the spring of the following season they produce 
rosette galls, later migrating back to the apple. The rosette 
gall has been separated from the leaf curl gall produced by 
Schizoneura americana, a species that is a frequent pest on 
elm trees. 




Fig. 85. — Woolly aphis on apple twigs. (Photo from Ohio Exp. Sta.) 



Remedies for the root form are difficult, but for orchard 
trees after removal of the earth, sprinkle tobacco dust on 
the roots and replace the soil. The use of 10 per cent, 
kerosene emulsion can also be recommended. Above ground 



FAMILY ALEYRODID^ 129 

the use of tobacco extract or 7 per cent, kerosene emulsion 
may be used. 

In another group of aphids we have the gall-making 
pemphiginse which cause conspicuous deformations upon the 
leaves of many different plants. Some of the more con- 
spicuous ones are the vagabond gall on cottonwood, and the 
poplar leaf galls. 

Grape Phylloxera. — The Grape Phylloxera is one of the 
very destructive insects of the grape-vine and is known over 
a wide territory, having been carried from America to Europe, 
where it caused a great deal of destruction to the vineyards, 
especially in southern France. It affects the roots of the 
vines and occurs on these during autumn, winter and early 
spring, but during midsummer migrates to the leaves, caus- 
ing the production of leaf galls, so conspicuous at that time. 
By the time these galls mature or the leaves ripen the insect 
migrates to the roots. The use of bisulphide of carbon 
injected into the soil is the most available remedy, but there 
is so much difference in the resistance of different varieties 
of grape that the cultivation of thick-leaved kinds is con- 
sidered advantageous. Where flooding is practicable, the 
submergence of the insects for a period of two or three days 
is effective. 

Numerous species of phylloxera occur on the leaves of 
hickory, walnut, and other trees, but for the most part are 
not considered of especial economic importance. 

Family Aleyrodidse — The next family in the series is the 
AleyrodidoB. These are forms which have a mealy covering 
on the wings and have the eyes divided, each compound 
eye being divided into two, and the antennae being located 
within the division of the eye. The adults are very similar 
but the larvae and nymphs which form scale-like bodies on 
trees have very distinct characteristics so that the species 
are to be distinguished by the study of these stages rather 
than of the adults. They resemble somewhat the scale in- 
sects, but the adult characteristics are quite different. The 
scales are quite distinctive. In many cases there is a fringe 
of white, waxy material which seems to act as an attach- 
9 



130 ORDER HEMIPTERA 

ment to the surface of the bark. This often Hfts the scale 
from the surface of the bark. There are cHstinct differences 
in the markings of the body and in the anal plates. A rather 
destructive form occurs on greenhouse plants, and is known 
commonly by the name of "white fly." In some instances 
it is very destructive. The eggs of the adults are laid on the 
leaves and the larvae fix themselves after a short migration 
and develop until they have reached the pupal, stage, and 
from this stage the adult winged form issues. The family 
is not so large nor so important as the scale insects — Coccidoe. 
Two species occur on oranges in Florida; one, the orange 
white fly, is often the means of serious loss in orange orchards. 
They are treated by sprays and by cultivation of certain 
parasitic fungi. 

COCCIDiE. 

The Coccidoe, scale insects, or bark lice, are to be considered 
as the extreme branch along the line of specialization found 
in this group. There are several subdivisions with various 
kinds of specializations. The group is characterized by the 
absence of wings in the females and the reduction of wings 
in the males to one pair, they are usually firmly attached 
to the plant on w^hich the larva has settled and even in 
forms not attached probable means of migration are limited. 
The males are winged but show distinct specialization in 
the reduction of the second pair of wings. These constitute 
simple, aborted, hook-like structures that can serve no pur- 
pose in flight. The same kind of reduction as in Diptera. 
The males also show a fairly distinct metamorphosis. The 
larvae change to a quiescent pupal stage and this gives rise 
to an adult two-winged male. The females are wingless 
and usually immovable, mating depends entirely upon the 
migration and flight of the males. 

Owing to the extent and the economic importance of this 
group, it seems desirable to give some account of the sub- 
families and to discuss somewhat in detail certain of the 
especially important economic species. Their sedentary 
habits permit a ready distribution, yet make it easy to 



COCCIDM 



131 



control them by proper laws for exclusion. In determina- 
tion, the appearance and color of the scale and the appear- 
ance it gives to the trees are very important. There are 
several subfamilies but the following include the American 
species of importance. 

The DactylopiinoB, including the mealy bugs and related 
forms, differs from other members of the family largely in 
the fact that the species are less fixed in habit. The mealy 




Fig. 86. 



-Orthezia solidaginis Sanders on goldenrod leaves, 
author.) 



(Photo by 



bugs are particularly active and capable of traveling about 
readily. They are covered with a whitish, mealy secretion 
from which they derive their name, and in temperate regions 
are found for the most part in greenhouses but there are a 
few native outdoor species. The common mealy bug of 
greenhouses {Psendococcus citri) is a very well-known pest 
and may be found in different stages of its life history in 
almost any greenhouse and frequently upon house plants 
if kept where there is moisture. Fumigation and the use of 
washes are available for their control. 



132 



ORDER HEMIPTERA 



An interesting subdivision of the group includes the 
Orthcziince which secrete a white calcareous secretion which 
appears in plates or filaments extending from the body, often 
as long parallel bars extending back some distance from the 
body. A rather common species in the Northern States is 
solidaginis, occurring on goldenrod. There also is included 
in this group the very destructive cottony cushion scale, 
Icerya purchasi, which for a time threatened the fruit 




Fig. 87. — Pulvinaria innumerabilis: adult females in position on twigs 
with egg sacs — natural size. (Howard, Div. Ent., U. S. Dept. Ag.) 



industry of California but which was brought under control 
by the importation of the Australian lady bird (Vedalia 
cardmalis) . 

The subfamily Coccincp includes what are termed the soft 
scales. The bodies of these are covered more or less com- 
pletely with a waxy secretion which adheres firmly to the 
body wall and furnishes a thick^ more or less rigid protec- 
tion to the body. Most of them adhere fixedly to the bark 
or leaves but in some cases a migration at the time of moult- 



COCCIDM 



133 



ing or when changing from the nymph to the adult stages 
may occur. 

Maple Scale (Puhinaria innumerabilis) . — The maple scale 
is a wide-spread and occasionally abundant and destructive 
species, attacking particularly the soft maple and occurring 
at times on other trees or woody plants. In this species 
the adults mature in autumn and winged males issue from 
the scale and mate with the females, the latter remaining 




Fig. 88. — Puhinaria innumerabilis: a, newly hatched young; h, female, 
third stage, from above: c, same, from side; d, male, third degree; e, same, 
natural size, on leaf and petiole; /, same, enlarged, on leaf petiole showing 
two specimens parasitized, all greatlj* enlarged except e. (From Howard, 
Buieau of Entomology, U. S. Dept. of Agriculture.) 



unwinged. They may, however, migrate from leaves to 
twigs or branches and attach themselves firmly for the 
winter, which is passed by the adult female only. In spring 
the eggs are developed and by early June a very large cottony 
mass is formed beneath the scale, lifting it from the bark, 
except at the anterior end, and within this large cottony 
mass an enormous number of eggs are deposited. Hatching 
of the eggs occurs shortly after the deposition and the larvae 



134 ORDER HEMIPTERA 

travel rapidly for a day or two, going especially toward the 
outer and upj>er branches where they fix themselves, and 
during successive moults remain attached to leaf or bark 
until autumn, when the a,dults mature, completing the life- 
cycle. 

Diaspinae. — The armored scales {Diaspiiioe) differ from 
the i)receding forms in that the waxy secretion separates 
from the body wall and forms an external shield or cover 
within which the scale insect is enclosed and w^ithin which 
there is soilie possibility of movements of parts, although 
the mouth parts are anchored quite permanently in the 
bark. Classification of the species in this division is com- 
plicated by the presence of this external scale, although in 
many species the external features of the scale are a fairly 
good basis for the recognition of the species. 

A microscopic examination is required to determine the 
species in many cases. The pygidium (the fused terminal 
segments of the abdomen of the female) includes the char- 
acters most often used, as it is highly chitinous so that it 
holds its peculiar characters even after a long time in a 
dried state. Specimens kept dry twenty to thirty years 
may be used for examination. The dorsal surface may have 
glands that produce waxy secretion forming the scales. The 
anal opening is also on the dorsal side. 

Upon the ventral surface the vaginal opening is a con- 
spicuous landmark and ordinarily grouped around this are 
small spinnerets which appear under the microscope as 
strongly chitinized circles. There are generally four or five 
groups. These groups are named according to their relation 
to the vaginal opening. The median or anterior group is in 
front of the vaginal opening and on each side at about equal 
distances are the cephalolateral or anterolateral group and 
the caudolateral group. These spinnerets or grouped glands 
are entirel}^ wanting in the San Jog6 scale. 

The marginal structure of the pygidium takes second 
place in the determination of species and the number and 
shape and modification of the lobes are very important. 
In some cases there are thickenings of the margin that closely 



COCCIDM 135 

resemble the lobes. The incision of the margin by their 
shape and extent afford characteristics of value. 

Spines on the lobes are commonly present and afford quite 
serviceable characters. There are generally two for each 
lobe — one on each of the dorsal and ventral surfaces. In some 
cases these spines are tubular and threads may sometimes 
be seen issuing from them. 

The plates are distinctly modified spines. They are gen- 
erally flattened and frequently notched. The simple forms 
differ from spines in that they do not have a globular base. 
Wax ducts appear as hairs on spines which extend into the 
body. 

Chionaspis Salicis. — The willow scale {Chlonaspis salicis) 
possesses a dense waxy structure overlying and separate 
from the body of the insect. The mouth parts are imbedded 
in the bark and sap wood. The head is pretty well marked 
but antennae and legs are reduced. There are two entirely 
different kinds of scales on the willow. The larger is an oval, 
somewhat elongated scale, the smaller narrow and with 
three rather fine ridges. The large scale is the female, the 
smaller the male. The growth of scales takes place during 
summer months; they increase in size by successive moults. 
As the larval scale is shed it is left attached to the new scale, 
and so on, often two or three are attached to the outer sur- 
face of the scale. By autumn these will have reached 
maturity, and mating will occur probably by early October. 
The males all die off immediately and the females deposit 
eggs and then shrivel up and die before winter. The female 
never leaves the scale at all. 

At the beginning of winter there is this mass of eggs 
protected under a scale as the means of carrjdng the insect 
over to the spring. They hatch probably during early June, 
possibly the latter part of May. Eggs are reddish-purple. 
The larvse crawl from under the scale and scatter out and 
make a special effort it would seem to get on new twigs and 
fresh growth of wood. They seem to travel upward in the 
lightest direction and this naturally carries them out to the 
ends of the twigs and leaves. During this migration period, 



136 ORDER HEM I PT ERA 

which lasts two or three (hiys, they may be distributed in 
several ways. A good breeze might carry them some little 
distance. They may be carried by birds. They may be 
carried on pieces of plant on which they occur, which is the 
means bv which most of the scale insects are distributed. 








Fig. 89. — Chionaspis furfurus. Scurfy scale on apple. (Photo from Ohio 

Exp. Sta.) 



Oyster-shell scale is named from the shape of its scale. 
It is a European species, but occurs as a widely distrib- 
uted species in this country and affects a number of host 
plants, principally the apple. The adults mature in fall and 
white eggs are deposited under scales and survive the winter, 
hatching early in June. The larvae then scatter and develop 
during the summer. 



COCCID^ 137 

San Jose Scale. — The San Jose scale is an introduced 
species which has been the source of an immense amount of 
loss in orchards, nurseries, etc. It presents some modifica- 
tions from the ordinary forms. It is small with an almost 
perfectly circular scale. The exuviae remain near the centre, 
giving it a somewhat nipple-shaped appearance. When 




Fig. 90. — San Jose scale: male adult — greatly enlarged. (After 
Howard.) 

abundant they give a very scurfy incrusted appearance to 
the twig on which they occur. The male scales are smaller 
and a little more oval in shape. The life history differs from 
most other species in that young are produced alive, the 
eggs hatching before extrusion, and the young develop 
rapidly, mature in a short time, and produce another genera- 
tion. There may be as high as four to six generations in a 



138 



ORDER HEMIPTERA 



season. It has been estimated that a single female may be 
the parent of about three and a half billions in a single 
season. Since there is no egg, but young are brought forth 
alive, they must have constant nutrition, and unless the scale 
is attached to living tissue the insects must perish, except 



/ 


A / 


/ 


'\ 


/ 


■f{ 


) 


\ .. 


\ 


'--a.*?. \^iv ' 






N' 


c 






''"-\ 










tli 


d 





Fig. 91. — San Jose scale: c, adult female containing young — greatly- 
enlarged; d, anal fringe of same — still more enlarged. (After Howard.) 



that mature females may assume a dormant condition dur- 
ing cold weather. The only means of transportation to 
distant points, therefore, appears to be upon living plant 
tissue, and this makes it possible to prevent its distribution 
by adopting restrictive measures through inspection and 
quarantine. 



COCCIDM 



139 



For measures of treatment where exclusion is not possible, 
there are two or three fairly effective remedies in the killing 
of the scale. One of these is kerosene emulsion, made by 
agitating kerosene and soapsuds. One gallon of water, 




Fig, 92. — San Jose scale on leaves and fruit. (Photo from Ohio Exp. Sta.) 

one-half pound of soap brought to the boiling point and then 
mixed (away from the fire) with two gallons of kerosene 
and then agitated into an emulsion by a force-pump or egg- 
beater. This is diluted with soft water, one part of emul- 
sion to eight or nine parts of water. 



140 



ORDER HEMIPTERA 



Whale-oil soap is sometimes used, but the most favored 
remedy at the present time is lime-sul])hur wash formed by 
boiling the ingredients together. This is applied by means 
of a spray-pump so that it covers the trees. If these appli- 
cations are made thoroughly the scales may be killed off to 
a great extent, though it is is hard to completely exterminate 
them. Badly infested trees will seldom recover and it is 
about as well to cut out and destroy such trees. Remedies 
that can be applied when larvae are travelling will be more 
effective, but in San Jose scale larvae are travelling most of 
the summer months. In those species where there is a 




Fig. 93. — Peach orchard injured l)y San Jose scale. Neglected, badly 
infested orchard at right and injured rows adjacent in spite of careful 
spraying with protection to rest of orchard at left. (Photo by author.) 



definite period for the larvae, spra^^ing even with clear water 
if the pressure is great w^ill reduce their numbers considerably. 
It is important to know the life histories perfectly. 

The Heteroptera include those forms which have wings 
thickened at the apex and in which the mouth parts arise 
from the most anterior portion of the head, and both in this 
character and in the wing structure are evidenth^ more 
specialized than the Homoptera. It is not possible to say 
that any of the Heteroptera present more specialization in 
certain lines than some of the Homoptera. 

The families are pretty well marked, and a number of 



CORISIDyE 141 

the groups are aquatic, a number terrestrial, and some 
arboreal. The aquatic forms are derived from the terres- 
trial. Most of them are obhged to come to the surface of 
the water to secure air at various intervals and this shows 
that they are modified from terrestrial forms. The aquatic 
forms pass the larval stage in the aquatic life but in most of 
the aquatic families the adults are also aquatic, though they 
may issue from the water and fly readily out of water. The 
eggs of aquatic forms are deposited on aquatic plants dis- 
tributed in the water and only in a few cases do they show 
marked peculiarities in the matter of egg deposition. In 
one of our common species, the smaller water bug {Zaitha 
flwninea), the eggs are deposited on the back of the male 




c h a 

Fig. 94. — Water bugs: a, water boatman, Corisa harrisii; b, Notonecta 

irrorata; c, Notonectaundulata. Enlarged X 1.42. (Photo by C. J. Drake.) 

by the female in a rather large mass, the eggs being set on 
end attached to the wing covers and are carried in this way 
for some time until they hatch. 

Of the terrestrial forms there are a considerable number of 
families. Some important species, chinch bug, squash bug, 
etc. The effect of the chinch bug on cereal crops is very 
damaging. 

Water Boatmen (Corisidce). — The water boatmen are small 
species. Their legs are modified for swimming, the hind 
ones being long, wide, and oar-like, having a series of cilia 
which aid much in swimming. The species are found in large 
numbers in ponds and streams, occasionally they fly in large 
swarms. Spring is the usual time when they are seen flying 



142 ORDER HEMIPTERA 

and are attracted very much by lights. They constitute a 
food supply for fishes and they themselves feed on other 
aquatic organisms. One species in Mexico is dried and used 
for food by the natives and is also sold in the markets as 
bird food. There is some question as to their economic 
importance. 

Notonectidse. — ^These are generally larger than the Corisidce. 
The striking thing about them is that they swim back down- 
ward, coming to the surface of the water at intervals for air. 
Our common species is Notonecta undidata. This species 
has a severe bite and it is best to handle it with care. 

Water Scorpions (Nejndce). — The water scorpions are 
characterized by a long respiratory tube at the end of the 
body; a very much elongated coxa in the forelegs so that 
the femur and tibia can be thrust out from the end of the 
body to catch prey. They are generally found in shallow 
water, secreted in dead leaves close to the bottom. How- 
ever, they are strictly dependent on air for respiration and 
get it by sticking this respiratory tube up to the surface of 
the water. They are strictly carnivorous, puncturing their 
prey and sucking the blood. If they are touched they feint 
and their legs may be broken off without any motion on 
their part. 

Belostomidae. — These are the giant water bugs and are the 
largest bugs belonging to this order. They have a short 
respiratory tube and a strong and somewhat curved beak, 
and can inflict a very severe bite. They are quite preda- 
ceous, feeding on young fish, and sometimes even those 
larger than themselves. Thus they are of distinct impor- 
tance as destroyers of fish. They go through all the stages 
of their life-cycle below the surface of the water. The eggs 
are laid under water on the stems of plants or in the case 
of one species on the back of the insect itself. The eggs 
are cemented so tightly that sometimes the shells remain 
long after the eggs are hatched. The young at first are 
nearly the form of the adults but without wings. They 
grow by successive moults and with gradual appearance of 
wing pads until they reach the adult stage. 



BELOSTOMIDM 



143 



Two species, one found in the Philippines and the other 
in South America, are much larger than those found here. 




Fig. 95.— Water scorpion {Ranaira americana). (Drawn by Jos. D. Smith.) 



144 



ORDER HEMIPTERA 



There are two large species commonly found in the United 
States, the Bclestoma americana, which has a groo\'e along 
the inner margin of the forefemur, while the Benacu.s' griseus 
has none. The latter is also slightly larger, has the hind 
tibiae broader and the legs not so distinctly annulated with 
dark rings. 




Fig. 96. — Giant water bug (Benacus griseus Say) : dorsal and ventral 
views. Slightly enlarged. (Original photo by C. J. Drake.) 



Water Striders (IlydrohaficloB). — This is a very interesting 
group. Their bodies are covered with a very fine velvety 
coat which sheds water, thus enabling them to live on the 
surface of water. They look somewhat like spiders, the 
legs are long and extend outward in a spider-like manner. 
The front pair are shorter than the others, being used to 
catch food. The antennse are short and are hard to dis- 
tinguish from the first pair of legs. Along with these forms 



REDUVIID^ 145 

there are several little shore-living species, of no economic 
importance, however. 

Predaceous Bugs. — The Assassin Bugs {Reduviidw). — 
The assassin bugs are rather large-sized insects with slender 
bodies and legs. The beak is rather strong and short and 




Fig. 97. — Water strider {Limnogonus hesione). (Drawn by Jos. D. Smith.) 

is fitted for punctm'ing insects. The species generally are 
predaceous, feeding very largely on destructive insects. 
Several species, however, puncture warm-blooded animals 
and suck their blood. The most familiar one of this kind 
is the "kissing-bug" or blood-sucking cone-nose. This 
is a strictly Southern species and is rarely found north of 

10 



146 



ORDER HEMIPTERA 



of the Ohio Ri\'er. It occurs in the Southern States and 
occasionally in Ohio. The masked bed-bug hunter is com- 




FiG. 98. — Blood-sucking cone-nose {Conorrhinus sanguisugus) : h, nymph; 
c, adult. Enlarged. (From Bur. Ent., U. S. Dept. Ag.) 




Yi(j^ 99. — The " kissing- bug " or masked bed-bug hunter (Redurius perso- 
natus). (After Howard, Div. Ent., U. S. Dept. Ag.) 

mon in both Europe and America. The wheel bug, so-called 
on account of the round thorax, is also found in the South. 



ACANTHIDM 



147 



The thread-legged bug is a very thin insect which, like 
the water scorpion and praying mantis, has the coxa of the 
front legs elongated for grasping. The damsel bugs {Nahid(B) 
are serviceable in eating leafhoppers and like pests. While 
the ambush bugs {Phymatidoe) are serviceable in reducing 
the number of destructive insects, they also show protective 
coloration to' a marked extent. Phymata erosa is our common 
species. It is commonly found in blossoms of goldenrod or 
other plants where it catches insects which visit the flowers. 

The Bed-bug Family (Acanthidce) .—These bugs are much 
flattened and are pretty generally predaceous or blood- 
sucking. The most common species, bed-bug {Cimex lectu- 




FiG. 100. — Phymata erosa: a, dorsal view; h, lateral view; c, front leg; 
d, snout— a, b, enlarged; c, d, more enlarged. (Riley, Div. Ent., U. S. 
Dept. Ag.) 

larius), is restricted to houses and is quite largely dependent 
upon human blood for food. It is almost entirely wingless, 
the wings being very small, owing to disuse, and thus beconi- 
ing entirely useless as organs of flight. This species is 
distinctly averse to light and hides during the daytime m 
cracks and crevices, coming out at night to feed. They are 
light colored when young and become darker with growth, 
and appear darkest just after a meal, which consists of blood. 
The feeding periods are far apart and the species is able to 
live for a long period without any supply of food. It is said 
that one can live a year without food. They cannot crawl, 
and depend upon being carried from place to place on cloth- 
ing. They are commonly found in cheap hotels and board- 



148 



ORDER IIEMIPTERA 



ing liouses and wlien once established in a place it is very 
difficult to get rid of them. The life history of the species 
is not very definitely known. 

The eggs, which are deposited upon furniture and in cracks 
and crevices, are white and rather long and cylindrical. 
They hatch in a few days, the young are of the same shape 
as the adult but are white. The young bugs moult five or 
six times before they are mature. The growth is very slow 








Fig. 101. — The bed-bug (Cimex lectularius) : a, adult female gorged with 
blood; h, the same from below; c, rudimentary wing pad; d, mouth parts. 
a and h much enlarged; c and d, highly magnified. (Marlatt.) Relapsing 
fever and kala azar are carried by the bed-bug. (Rosenau.) 



and irregular, all depending upon opportunities offered for 
getting food. This species does not have a regular life-cycle 
as insects which live out of doors under the influence of the 
seasons. Bed-bugs can be killed with sufficient effort, cor- 
rosive sublimate being one of the best remedies. Kerosene, 
gasoline, or hot water prove very effective. Constant 
attention to furniture and the destruction of those bugs 
which appear is the most essential thing in their destruction. 
Bed-bugs are of considerable importance from the fact that 



CAPSIDM 



149 




Fig l^2.-Coauilleiia mimetica Osborn: a female dorsal jiewjb female 
(After Osborn. From drawings by Miss Kmg.) 



150 



ORDER HEMIPTERA 



they have the power of transmitting blood diseases from 
one person to another. 

The Tingitid(B, or lace bugs, are common on thorn bushes, 
sycamore, oak, walnut, and many other plants. 

The leaf bugs {Capsidm) are of some economic importance, 
from the fact that they attack the leaves of fruit trees in 




Fig. 103. — Sericophanes ocellatus Reut: dorsal views: a, macropterous 
male; b, micropterous female; c, macropterous female; d, side view microp- 
terous female; e, macropterous female; /, wing of micropterous female; g, 
micropterous female; h, male abdomen beneath. (After Osborn. Drawn 
by Miss C. M. King.) 



the spring, puncturing them and sucking the plant juices. 
They are also quite common in meadows and pastures. 

The tarnished plant bug is a very important species 
affecting orchards where it attacks the buds and blights 
them. It also works on clover and does great damage to 
strawberries, causing ''buttoning." 

Certain species in this family show a very strict resem- 



LYGAEID^ 151 

blance to ants, and this is especially so in the case of the 
species of Pilophorus, Coquilletia, and Sericophanes, 

One of these species, Coquilletia mimetica, carries this 
resemblance to the extreme in the development of small 
elevations on the first and second abdominal segments 
which correspond closely to the first abdominal segment of 
the ant. The female in one form is entirely wingless, but a 
full-winged form of female also occurs, and the males are 
full-winged. 

Another species, Sericophanes ocellatus, shows somewhat 
less modification in that the wings are not completely lost 




Fig. 104. — Chinch bug (Blissus leucoptcrus) : adult of long- winged form, 
much enlarged. (From Webster, Div. Ent., U. S. Dept. Ag.) 

but are retained as short rudiments which extend over 
the basal segments of the abdomen. The effect as a whole, 
however, closely simulates the appearance of an ant. 

The family Lygaeidse includes the chinch bug and numer- 
ous other small bugs, but few of which are of economic 
importance. 

Chinch Bug {Blissus leucopterus) . — ^The chinch bug is very 
important as a farm pest. It has a long, slender body with 
parallel sides and four-jointed antennae. The body is black 
and the wings white. It occurs all over the Mississippi 
Valley and south to Central America but it is most serious 



152 



ORDER HEMIPTERA 



in Illinois, Missouri, Kansas, Nebraska, Iowa, and parts of 
Indiana, and occasionally in parts of Ohio. The losses due 




Fig. 105. — Chinch bug: a, b, eggs; c, newly hatched larva or nymph; 
d, its tarsus; e, larva after first moult; /, same after second moult; g, last- 
stage larva; the natural sizes indicated at sides; h, enlarged leg of perfect 
bug; j, tarsus of same, still more enlarged; i, proboscis or beak, enlarged. 
(From Eiley.) 

to this insect are large, being estimated as high as $60,000,000 
and amounting to $20,000,000 in one State alone in one year. 




Fig. 106. 



-Chinch bug. Adults of short-winged form, much enlaiged. 
(Alter Webster, Bur. Ent., U. S. Dept. Ag.) 



It has two generations a year and the winter is spent in 
the adult stage under bark of trees, bunches of grass, fence 
corners, etc. Often if a thicket is near they will migrate 



LYGAEIDM 



153 



to it. In the prairies they hide in the grass and emerge in 
the spring. The female begins to deposit eggs in April and 
May. This is done gradually and extends over a period of 
about three weeks. This early deposition is usually done 
about one-half inch under the ground on the stems of spring 
or winter wheat. The eggs are white and very minute and 
have four little projections at the head end. They hatch 
in three or four days after deposition, into minute little 




Fig. 107. — Chinch bug on corn. (Photo from Ohio Exp. Sta.) 



white bugs with small red spots, having the same shape as 
the adult but lacking in wings.. They are unable to feed on 
plants outside of the grass family, migrate to corn after the 
wheat is cut and while some have wings fully developed they 
usually all move on foot. At this time they can be easily 
killed. The eggs of the second brood are laid on the corn 
stalks. Before cold weather comes there is an extensive 
migration, probably accompanied by mating, and the insects 
hibernate. One group matures in the summer and dies while 



154 ORDER HEMIPTERA 

the second groui) matures and liihernates and produces a 
spring brood. 

The control of the chinch bug is based on tlie use of barriers 
between the wheat fiekls and the corn, and a dust furrow 
is good, or the placing of a crop that they will not feed on, 




Fig. lOS. — Chinch bug. (Photomicrograph from Ohio Exp. Sta.) 

such as potatoes, between the corn and wheat. When the 
bugs first go into the corn they stop on the first few rows 
and when there they may be killed with kerosene emulsion. 
Rotation of crops is a good thing and the burning of waste 
grass and weeds in the late fall gets those that live there. 



COREIDM 



155 



They may be ploughed under in the stubble but this must 
be at least five inches deep. The introduction of a fungus 
which was fatal to the bug was tried extensively but without 
success sufficient to warrant its recommendation as a reliable 
measure of control. 

Family Coreidae. — This family includes the squash bug 
and a number of other prominent species. They are dis- 
tinguished by the robust body, numerous veinlets in the 
membrane and the four- jointed antennae. The common 







^^sf^' ^ 



Fig. 109. — Chinch bug. Hibernating quartors. (Photo from Ohio 
Exp. Sta.) 



squash bug is a very familiar species, a large dark colored 
insect about three-fourths of an inch long. It hibernates 
in adult form secreted around buildings or under debris on 
the surface of the ground and in early summer deposits eggs 
on squash or melon vines. The nymphs puncture the leaves, 
and their attack upon the plant often results in a complete 
withering, so that if the insect is numerous the crop may be 
seriously affected. The eggs are small glistening objects 
attached in loose clusters upon the under side of the leaf. 



150 



ORDER IIEMIPTERA 



The nymphs are at first without trace of wing pads, but in 
successive instars the wing pads increase in size. The 
different instars are sliown in the accompanying figure. 




Fig. 110. — Anasa tristis: a, mature female; h, side view of head, show- 
ing haustellum; c, abdominal segments of male; d, same of female; a, 
twice natural size; b, c, d, slightly more enlarged. (From Chittenden. 
Div. Ent., U. S. Dept. Ag.) 




Fig. 111. — Anasa tristis nymphs: a, newly hatched; b, second stage; c, 
third stage; d. fourth stage; e, fifth stage — all about twice natural size. 
(From Chittenden, Div. Ent., U. S. Dept. Ag ) 

Box Elder Bug {Leptocoris trivittatus) . — The box elder bug 
is black with red lines, and since this species has been migrat- 



COREIDJE 



157 



ing eastward from an original westward habitat it is of 
interest to note its progress. In recent years it has been 
observed as far east as Ohio and it is quite likely to extend 




Fig. 112. — Eggs of Anasa tristis: o, from below, showing point of attach- 
ment; b, from side, showing place of escape of nymph; c, sculpture of egg; 
d, egg cluster; a, b, about five times natural size; d, one-fourth enlarged; 
c, greatly enlarged. (From Chittenden, Div. Ent., U. S. Dept. Ag.) 




Fig. 113. — Leptocoris trivittatus: a, eggs enlarged, natural size above, 
b, c, d, different stages of immature bugs; e, adult; all enlarged; natural 
sizes indicated by hair lines. (All after Marlatt except e, which is after 
Howard, Div. Ent., U. S. Dept. Ag.) 



15S 



ORDER IIEMIPTERA 



its range to the Atlantic coast. It attacks particularly box 
elder trees and the young probably feed upon this in prefer- 
ence to other plants, but the adults in autumn scatter quite 
widely and in some instances are quite troublesome in 




Ficj. 114. — Corizus crasaicornis. (After Hambleton.) 



houses because of their tendency to fall into all kinds of 
objects such as milk pans and other food receptacles. 

The species of Corizus are small, robust forms occurring 
on a very great variety of plants and commonly noted along 
roadsides and in clover fields. 



PENTATOMID^ 



159 



Stink Bugs (Pentatomidce) . — Stink bugs are rather broad 
oval-shaped insects with four- or five-jointed antennae, the 
wings He flat and the membranous tip of the second pair 
are uncovered. They have a rather large scutellum lying 
between the bases of the wings. The characteristic odor of 
the stink bugs is not confined to this particular family. A few 
members of this family are of economic importance. The 
green soldier bug is very destructive to peaches in the northern 
part of the United States. The spined soldier bug (Podisus 




Fig, 115. — The spined soldier bug {Podisus maculiventris) : adult at left, 
nymph at right; much enlarged. (Chittenden, Div. Ent., U. S. Dept. Ag.) 



maculiventris) is not very large and is characterized by very 
distinct spines which project from the side of the body. 
It is very distinctly a predaceous bug. It is credited with 
killing the larvse of the Colorado potato beetle, and it also 
feeds on caterpillars and other insects. On the whole it is 
counted as being very beneficial. 

The harlequin cabbage bug {Murgantia histrionica) is 
one of the species common in the Southern States, and if it 
becomes abundant is a very serious pest. Ohio is its northern 



160 



ORDER HEMIPTERA 



limit. It can be controlled by spraying with kerosene emul- 
sion during the larval stage. 

The subdivision Parasifa includes the suctorial lice, and 
they present perhaps the greatest divergence from the 
normal form, the extreme being in the direction of reduction 
due to parasitism. They are entirely wingless; they have 
a reduction of the mouth parts which is extreme. The beak 




Fig. 116, — Stink bug: a, adult; b, eggs attached to leaves; c, d, e, f, 
details of egg structure. (Bur. Ent. U. S. Dept. Ag.) 



is reduced to a single segment through w^hich the tubular 
setae are projected — a derivation from the three- or four- 
jointed beak of the normal forms. There is a distinct 
reduction or retrogression in the wings and mouth parts, 
but a distinct specialization in the structures by which 
they clasp the hairs or feathers of host forms. Tarsal claws 
are very large and strong and are provided with ridges or 
roughened areas which seem to strengthen the hold upon 



PARASITA 161 

the hairs, and in a few forms there are still other speciaHzed 
clasping structures to strengthen this hold. In some the 
antennae serve to help hold on. In one form there is a 
tubercle developed so that it fits against the pair of legs 
next forward so that it seems to act as a clasping organ. 
These suctorial lice are limited to mammals for their hosts. 
The mouth parts are doubtless adapted to the reaching of 
the capillary blood system in these hosts and in their life 
history they show adaptation to the parasitic habit, the eggs 
being glued to the hairs, the larvse on first hatching being 
capable of attaching themselves to the hairs so that the 
entire life-cycle is distinctly parasitic. Their migrations 
from these host forms are simply for the purpose of scatter- 
ing to other individuals of the same species. There is a 
rather distinct tendency for the individuals to migrate to 
younger animals of the same species. There is not a very 
evident series of broods in a year — they probably breed 
rather promiscuously. They have a constant host and 
constant warmth. Three species affect man and the horse, 
ox, sheep, hog, dog, and a great number of other mammals 
are known to support one or more species. 

Short-nosed Ox Louse {Hcematopinus eurysternus Nitzsch). 
— The short-nosed ox louse is the common species occurring 
on cattle. The full-grown females are about one-eighth 
to one-fifth of an inch long, and fully that in wi^th, while 
the males are a little smaller and proportionately a little 
narrower. Aside from the difference in size the sexes differ 
very decidedly in the markings and structural features upon 
the under side of the body. The female is bluish leaden or 
gray in color. The males have a broad black stripe running 
forward from the end of the body to near the middle of the 
abdomen, as shown in Fig. 117. The females have no 
indications of this stripe, but the black, broken band of the 
upper side of the terminal segment extends slightly around 
on the under side. The most important character, however, 
is the presence of two little brush-like organs on the next 
to the last segment, as shown in Fig. 117. 

The head is bluntly rounded in front, nearly as broad as 
U 



162 ORDER HEMIPTERA 

long, and witli the antennjv situated at the sides midway 
from tlie posterior to the anterior })orders; behind these 
are located slight eminences upon which may be found the 
small eyes, which are seen with considerable difficulty. At 
the front of the head may be seen the small rostrum or beak, 
the end of which is usually near the surface, but which is 
capable of extension or retraction. The end of this beak is 
armed with a double row of recurved hooks (see Fig. 115). 




Fig. 117. — Hoematopinus eurysternus: a, female; h, rostrum; c, ventral 
surf are of the last segments of the male; d, same of female; e, egg; /, surface 
of same greatlv enlarged. (Author's illustration, Bur. Ent., U. S. Dept. 
Ag.) 

Hog Louse {Hoematopinus vrivs). — The hog louse is one 
of the largest species of the family, full-grown individuals 
measuring a fourth of an inch or more in length. It is of a 
gray color, with the margins of the head and thorax and 
most of the abdomen dark. The head is quite long, the 
sides nearly parallel, with strong eminences just back of 
the antennae, which are set on the sides of the head, midway 
from rostrum to occiput; the legs are lighter, with dark 
bands at the joints; the spiracles are inclosed by a black 



PARASITA 



163 



chitinous eminence, and there is a broad black band on the 
last segment, broken near the middle. (See Fig. 118.) 

The male has the abdomen marked beneath with a large 
black area extending forward from the end of the terminal 
segment, so as to occupy the central portion of the last 
three se2:ments. 




Fig. 118. — Hcematopinus urius: a, female; b, ventral view of posterior 
segments of male; c, leg, showing protractile disk of tibia — enlarged. 
(Author's illustration, Bur. Ent., U. S. Dept. Ag.) 



A curious provision is found in the feet for strengthening 
the hold upon the hair. It consists of a circular pad-like 
organ or disk in the outer portion of the tibia, which is 
received in a conical cavity in the end of the tibia, and which 
can be forced out so as to press upon the hair held between 
the claw of the tarsus and the end of the tibia. 



164 ORDER HEMIPTERA 

On account of the thinness of the hair, the application of 
remedies, where necessary, is quite eas}^ Washes of tobacco 
water or dilute carbolic acid, and the application of kero- 
sene in lard, or kerosene emulsion by means of a force pump, 
sulphur, ointment, etc., are recommended. The application 
of fine dust may be provided for naturally by allowing the 
hogs a chance to roll in a roadway or any place well supplied 
with fine dust. Where this is impracticable the dust, ashes, 
or powdered charcoal may be applied directly to the neck and 
back of the infested animal. The species is not known to 
attack any other of the domestic animals, and hence no pre- 
cautionary measures in this direction are necessary. 



CHAPTER VI. 

NEUROPTERA AND ALLIES. 

The insects with complete metamorphosis include first 
the Neuroptera which are represented by the lace-winged 
fly, ant lion, etc. These are separated from the preceding 
groups by the fact of the complete metamorphosis, and this 
order includes groups which are quite distinct from each 
other and have biting mouth parts and rather densely net- 
veined wings. 

Order NEUROPTERA. 

Of the first family SialidcB, the Corydalis cornuta is the 
most prominent. The larvae live in running streams and 
under stones. Their structure and life-cycle furnish a 
good example for the group. The larva is strictly aquatic 
with gills which enable it to live in the water, but it can sur- 
vive out of water if the gills are moistened. The adults 
appear in the summer, mainly in the early part of summer, 
and the eggs are laid during the summer months, generally 
about midsummer, and deposited in large masses on the 
leaves of trees overhanging water. The larvae on hatching 
drop at once into the water and begin an aquatic existence. 
They feed on the larvae of other aquatic insects, and their 
life-cycle occupies three years. They are in the water for 
about two years and eleven months; the pupa stage, passed 
in muddy banks, as well as the adult stage being short. 
The larva changes to a pupa which is quite different from 
the larval stage and different also from the adult. They, 
are counted excellent as fish bait, and this is perhaps their 
most direct economic value. 

The Mantispidce have very prominent front feet, wings lie 
flat over the back and resemble a small form of the mantis. 

The family Chrysopidoe, which includes the lace-winged 

(165) 



166 



NEUROPTERA AND ALLIES 



flies, lias quite a ditt'erent larval hahit, Ix'ing carnivorous but 
not aquatic. Lar\';e are fre(iuently called the "aphis lions" 
as they are destructive to aphids. They are most commonly 
found on trees on which a])hids are abundant. 




Fig. 110. — Corydalis cornuta, female. (Photo by autlior.) 



The adults are very delicate with very thin, transparent, 
irridescent wings; brilliant golden eyes which stand out 
prominently (therefore called golden eyes) ; wings closely 
net-veined and bodies slender and cylindrical. The eggs are 



ORDER NEUROPTERA 



167 



deposited on leaves or twigs and are elevated on stalks, 
each egg standing up on a very distinct thread or pedicle. 
This is considered to be for protection of eggs from newly 




168 



NEUROPTERA AND ALLIES 



hatclied larvae of the same colony. The eggs are deposited 
in this way by the adult touching the abdomen to the sur- 
face of the leaf, then raising it quickly so that a thread of 
glutinous secret'on is drawn out. This hardens quickly 
and the egg is left at the tip of the thread. The larvae on 




Fig. 121. — Chrysopa oculata: newly hatched larva, with under side of 
head and claw at side — greatly enlarged. (From Marl alt, Di\. Ent., U. 
S. Dept. Ag.) 

hatching eat up the plant lice in the immediate vicinity. 
They are active and run about readily and have prominent 
jaws which are sickle-shape, tubular, and adapted for suck- 
ing the body fluids of the plant lice. When they have passed 
the larval stage they form a small spherical cocoon in which 
they pass the pupa stage and from which the adults emerge 



ORDER MECOPTERA 169 

shortly afterward. They produce a number of generations 
each year. 

Ant Lions {Myrmeleonidw) . — The ant Hons are closely 
related to the preceding. They look much tne same, and 
the only difference is the large antennae which stand out 
and are thickened at the tip. They have large, equal-sized 
wings and long, cylindrical abdomens. The wings are dis- 
tinctly net-veined. These ant lions appear in midsummer 
as adults and eggs are deposited presumably in the latter 
part of the summer. Whether they pass the winter in the 
egg stage or whether the larvse are partially developed is 
uncertain. But during the early part of the season and a 
large part of the summer the larvae may be found in sandy 
places forming little pits in the sand in the bottom of which 
they secrete themselves for the capture of ants and other 
small animals which may wander into the pits. They travel 
backward in changing their location, moving just beneath 
the surface and leave a very definite furrow on the surface 
of the sand. At one end of the furrow is usually a pit where 
the larva is secreted. After acquiring their growth they 
build a little spherical cocoon and within this they change 
some time later to the chrysalis stage. The adult stage is 
reached in, possibly, a two-year cycle. 

Order MECOPTERA (Scorpion Flies). 

In this order the species are usually four- winged, although 
in some cases the wings are reduced or aborted. The wings 
when occurring are not folded, have numerous veins, and 
often are marked with distinct spots or blotches. The head 
is much modified, being elongated so as to form a sort of beak 
at the end of which are the small mandibles and the other 
mouth parts. The metamorphosis is complete and the larval 
stage is somewhat caterpillar-like in general structure. 

The order includes the family Paiiorjndce and in this 
family are a number of common species, but few of them have 
any particular economic importance. They have usuall}^ 
eight pairs of prolegs or abdominal legs so that the}^ may 



170 NEUROPTERA AND ALLIED 

l)e (listinguislRMl from the l{'])i(l()])t(T()Us hir\'{i' which liave, 
as a rule, only five pairs. 

The s])ecies of liiffaru.s are somewhat common, usually 
found in woodland, and lia\'e some resemblances to the 
crane flies, but are easily distinguished by the presence of 
four wings. The genus Borcus is remarkable for appearing 
in the winter time and occurring in great numbers on the 
surface of snow. 

Order TRICHOPTERA (Caddice Flies). 

This order is of particular interest scientifically because 
it appears to be the primitive group from which the order 
Lepidoytera has been derived. The mouth parts are man- 
dibulate, the metamorphosis is distinct, the larval forms 
caterpillar-like but all the species are aquatic and show 
distinct specialization for aquatic existence. In the adults 
the body and wings are covered with minute flattened or 
scale-like appendages which approach the condition found 
in the Lepidoptera and except for the mandibulate mouth 
parts the group may be considered as distinctly connected 
with the Lepidoptera. In some forms the wings are opaque 
and the general appearance is extremely like some of the 
minute moths. 

Perhaps the most notable feature in the group is the 
larval habit of forming cases or tubes within which they live. 
These cases are made of a variety of materials, in some 
species from minute pebbles, minute mollusk shells, and in 
many cases w^ith fragments of aquatic plants or various kinds 
of debris occurring in the water. The cases are constructed 
shortly after the larvse hatch and are enlarged with the 
growth of the insect. The head and thoracic legs are 
projected from the tube, and the tube moved around by its 
adherence to the posterior part of the body. Some species 
have a habit of making delicate nets or traps in the water 
by means of which they catch aquatic animals for food, 
but in most of the species the larvse travel around freely and 
feed upon aquatic vegetation. The tubes or caddices formed 



ORDER TRICHOPTERA 171 

by these insects have been found in rocks of the tertiary 
period, so that it may be assumed that the aquatic case- 
making habit had developed as far back as this period 
in geological times. Aside from the fact that these may 
furnish food for other aquatic organisms there is little 
economic importance to be attached to them. The adults, 
while occurring in abundance, do not feed upon any culti- 
vated crops, and they rarely appear in such swarms as the 
May flies, so that there is no especial annoyance from their 
abundance. 



CHAPTER VII. 
COLEOPTERA. BEETLES. 

The Coleoptera, or the order of beetles, is one of the immense 
groups of insects, both in species and individuals. It is also 
one of the most distinctly marked groups. In some ways 
it is more specialized, in others more generalized. The 
wing structure is specialized, the horny front wings which 
are useless so far as flight is concerned being modified to 
serve as covers for the wings and for the abdomen. The 
hind wings are the organs for flight. Reduction of the front 
wings is to be noticed in a number of cases and in some 
species they cover only a small portion of the body. 

The Coleoptera and Diptera so far as wings are concerned 
are about equally specialized. In the mouth parts the Cole- 
optera are very much less specialized than the Diptera — they 
retain the primitive structure. The mandibles are some- 
times reduced but are functional in the adult stage and 
sometimes very strongly developed. They are not modified 
into suctorial organs. 

The metamorphosis is complete and the stages quite 
distinct. There are the four stages common to insects with 
complete metamorphosis and in some groups the larvse are 
further specialized, so that there are two or three different 
larval forms (hypermetamorphosis) . The beetles have been 
studied perhaps more than any other group unless it be the 
Lepidoptera. They are more easily preserved than most 
insects and often of striking form or conspicuous colors. 
The beetles probably number at least 100,000 species, and 
in this country 10,000 or 12,000 species are recognized. 
A considerable number of these are of economic importance. 
The group is separable into two quite distinct divisions. 
(172) 



GROUND BEETLES 



173 



the Rhyncophora are the more speciaUzed. The head is 
drawn out in a snout and the mandibles are much reduced 
in size. The larval forms are more specialized, usually fitted 
for living within seeds or parts of plants. 

In the arrangement of families the tiger beetles are usually 
placed first, but it would seem fully as proper to place Cara- 
bidcB in this position. 

Tiger Beetles (Cicindelidoe) .—The tiger beetles are found 
along roadsides, bare ground, or sandy beach. It is not easy 
to get the larval forms. The larvse are carnivorous and 
make little burrows in the earth and catch insects that come 
along at the surface. 





Fig. 122. — Calosoma scrutator. 



Fig. 123. — Lebia grandis, 
an important enemy of the 
potato beetle. Enlarged. 
(Chittenden, Div. Ent., U. S. 
Dept. Ag.) 



Ground Beetles (Carabidce).— The ground beetles are less 
specialized. They live usually at the surface of the ground 
and the larvse are provided with three pairs of normal legs 
and run about readily and are in fact quite primitive in 
appearance and habits. They are, as a rule, carnivorous, 
but a few species attack plants. 

Some of the more important beneficial species are the 
common ground beetle {Calosoma calidum), a black species 
with a series of metallic golden spots, abundant over a large 
part of the United States, and which feeds commonly on 



174 COLEOPTERA— BEETLES 

cut worms, caterpillars, etc. The searcher (^alosovia scruta- 
tor, a })rilliaiit green species with metallic border on elytra 
and mar<i:in of })r()thorax which, while a general feeder on 
ground-li\'ing insects, is also credited with climbing trees 
to feed upon canker worms. The Calosoma sycophanta, an 
old-world species that is especially useful in keeping the 
Gij)sy moth in check, has been introduced into INIassachusetts 
in hopes that it may assist in control of this pest. 

There are several families of aquatic Coleoptera which live 
almost entirely in water, although at times the adults issue 
and fly. The carni\'orous water beetles ( DysticidcE) have 
peculiar circular or oval sucking disks on the front legs, and 
are distinctly aquatic, the adults appearing out of water, 
and like the ground beetles, they feed quite exclusively upon 
other animal life and doubtless occupy a somewhat impor- 
tant place in the relations of aquatic forms. 

The Hydro philidcE are more distinctly herbivorous and 
may be considered as water scavengers, feeding upon vege- 
table debris and serving as important members of the 
aquatic association. It is a large family, including a great 
many genera and species, but from their habits are naturally 
of little economic importance. 

The GyrinidoB or whirligig beetles are quite remarkable 
for their movement on the surface of water. They dart 
around with the greatest rapidity, making all sorts of irregu- 
lar movements but when a group of them are together they 
form a bewildering array of darting forms. Although 
dozens or even hundreds of them may be in a group they 
seldom if ever seem to have a collision among the different 
individuals in the cluster. A remarkable feature in their 
structure is the separation of the compound eye at the side 
of the head so that the upper portion is abo\'e water and 
the lower portion submerged. They are said to feed mainly 
upon flies and stranded insects of various kinds that are 
caught on the surface of the water. One of our common 
species is the Dineutes americana. 

Family Platypsyllidse. — The PJcdypsyUidw is a small 
family including a very remarkable parasite of the beaver. 



FAMILY COCCINELLID.E 175 

The female is about 2J mm. in length, and ovate in form with 
very short wing pads so that the abdominal segments are 
exposed. The eyes and wings are both aborted. 

Family Silphidse. — The Silj^hidce, carrion beetles, are 
very distinctly scavengers and where there is an accumu- 
lation of decaying organic matter they doubtless serve a 
valuable function in disposing of such material that is 
detrimental. 

Sexton Beetles {Necrophorus). — The sexton beetles are 
the largest of the family. They bury small mammals such 
as rats or mice and upon these lay their eggs. The larva 
then feed upon the decaying flesh. ^ 

The species of Silpha are commonly found about dead 
fishes or carcasses of dead animals and both the adults and 
larvae feed upon the rotting material. 

Rove Beetles (StaphylinidoB).— The Staphylinidce are also 
largely scavengers. The group is a very large one including 
many hundreds of species. They are characterized par- 
ticularly by the structure of the wing covers which extend 
only to the base of the abdomen. The hind wings are 
folded by means of hinges on the wing margin so that they 
can be attached under the short wing-covers. The abdomen 
is left exposed and as the joints are flexible it can be moved 
about readily and the tip is used in manipulation of the wings 
preparatory to flight, or when they are folded after flight. 

Several other families related to this division must be 
passed over. 

Family Coccinellidse. — Lady Bugs. — These are abundant 
and very important insects, since practically all the members 
of the family are carnivorous and feed upon insects which 
for the most part are very destructive. They are especially 
serviceable in the control of plant lice and scale insects. 
The adults are short, generally hemispherical or oval, 
convex above with under side flattened. Usually they are 
rather conspicuous: some are red with yellowish or black 
spots, while others are black with red or yellowish spots. 

The larvae are very voracious insects and feed quite ex- 
clusively upon insects, so that they are considered of special 



176 



COLEOPTERA —BEETLES 



service and pains should he taken not to destroy them. They 
are short, flattened, rather broad, and usually with rather 
prominent spines or hairs as indicated in the accompanying 
figures. 




Fig. 124. — A lady bug (Hippodamia convergens) which preys on the 
Colorado potato beetle. Enlarged. (Chittenden, Div. Ent., U. S. Dept. 
Ag.) 




Fig. 125. — Spotted lady bug (Megilla inaculata): a, larva; 6, empty 
pupal skin; c, beetle, with enlarged antenna above. All enlarged. (From 
Chittenden, Div. Ent., U. S. Dept. Ag.) 



A number of species are abundant and of special service 
in various parts of the United States. Some of these are 
figured, and further description will be unnecessary. 



FAMILY CUCUJID.^ 



177 



Vedalia. — One species of particular interest is the Vedalia. 
This was introduced into Cahfornia for the purpose of con- 
trolHng the cottony-cushion scale and was so efficient in this 
respect that the scale insect has become of little economic 
importance. 

Family Cucujidae. — Saw-toothed Beetle. — The family Cucu- 
jidce includes, with other pests, the saw-toothed beetle 
(Sylvanus siirinamensis) , probably one of the most frequently 
noticed pests of stored cereal foods, especially those in 
packages. It is a little, dark red-brown beetle with the 




Fig. 126. — Adalia bipundata: a, larva; h, mouth parts of same; c, 
claw of same; r^, pupa; e, ad\ilt; /, antenna of same. All enlarged. (From 
Marlatt, Div. Ent., U. S. Dept. Ag.) 



edges of the prothorax strongly toothed. It is found in a 
great variety of food substances, including breakfast foods, 
yeast cakes, nuts, and dried fruits. 

All stages of the insect may occur in these substances, 
the larva being a slender, somewhat flattened creature, the 
pupa being about the shape of the adult. The adult tunnels 
through cases or migrates from place to place, depositing its 
eggs adjacent to the materials in which the larvae will grow. 
There are probably several generations each year, especially 
in the food materials that are in warm situations. They 
should not be present in fresh-packed cereals, but owing to 
12 



178 



COLEOPTERA— BEETLES 



tlie fact tlmt tliey become very numerous in mills it is quite 
probable that eggs may be included in the package and the 
larvse developed later. 

Family Lyctidse. — The family Lyctidce includes a number 
of wood-feeding species, for which the powder-post beetle 
(Lyctvs planicoUis) will serve as a fair example. 

Dermestidse. — The DermestidoB are forms that live on 
decaying animal matter. Good examples may be found by 




Fig. 127. — The saw-toothed grain beetle: a, adult; b, pupa; c, larva 
or grub. Greatly enlarged. (After Chittenden, Div. Ent., Bull. 4, n. s., 
1896, U. S. Dept. Ag.) 



examining dead fish and other decaying organic matter. 
Some of the species are museum pests, and troublesome in 
bird collections, and a very particular pest of insect collec- 
tions. On account of this it is necessary to keep collections 
in insect-proof boxes or else fumigate with carbon bisulphide. 
Larder Beetles (Derviestes lardariiis). — The adults appear 
particularly in early summer and the eggs are deposited on 
or near materials that furnish food for the larvae. The eggs 



FAMILY DERMESTIDM 



179 



require probably only a few days for hatching, long enough 
when laid on insects, so that it is possible for the insects to 
be transferred from one box to another and to introduce 
them into new boxes. In case of hams and bacon, these 
eggs may be on the hams when they pass from one dealer 
to another. The larvae grow most rapidly during the sum- 
mer months and if there are any distinct broods it would 
be the rapidly developing generations in the summer time. 
But the broods are not very sharply marked. There may 
be two or three broods, but the development is irregular 
enough, so that they are developing at all times of the year. 
The larvae do the feeding and devour the tissue, and the 




Fig. 128, — A powder-post beetle (Lyctus vlamcollis) : a, larva; b, adult; c, 
pupa; line to right of adult represents natural length. (Chittenden, Div. 
Ent., U. S. Dept. Ag.) 



pupation takes place early. The larvae may burrow through 
paper or wooden cases and then give rise to adults in a 
comparatively short time. 

Museum Beetle. — A related species — the museum beetle — 
is more a museum pest and less a pest in other ways. It 
lives in skins of mounted animals and other dried animal 
tissue. 

Carpet Beetles. — Closely related is the carpet beetle, which 
is a pest in fur and woollen goods and seldom if ever known 
as a pest in museums. It is fond of woollen carpets and 
furs. These seem to be its particular food supply. It was 
introduced from Europe and has spread over the entire 



180 



COLEOrrEHA— BEETLES 



country but is not very abundant for tlie most part. It 
is less abundant where rugs are used than where carpets are 
used. 

Click Beetles {FJatcridcp). — Click beetles are interesting on 
accoiHit of structure and their habits which are of economic 
importance. They make a sudden click and throw them- 
selves up into the air. This is produced by a little s})ur on 
the prothorax which fits into a little pit in the mesosternum. 
This is characteristic of the entire family and is not found 
in any other family. Its purpose is to throw the insect into 
the air and allow it to turn over. The larva? are called 




Fig. 129.- — Click beetle and wire worm {Melanotus communis): a, 
beetle. (After Bruner.) 



larva; h, 



wire worms. These are very troublesome pests. INIany of 
them are primarily grass-root feeders and will be found as 
larvae in grass lands, the larvse living just below the surface 
of the soil, and feeding mainly on the roots of the grass. 
When the land is plowed and planted in corn or some other 
crop the wire worms attack this other crop, sometimes in 
a much more noticeable manner than they do the grass. 
The larvae are not capable of migrating very great distances, 
and must depend on the vegetation that is present where 
they are hatched. The length of the larval period is show^n 
by their presence in a field of corn three years after it has 



BUPRESTIDjE 181 

been plowed from grass. Many of the species have never 
been traced through in detail, but those that have been traced 
show them to be grass-feeding species, and the eggs are 
deposited on grass lands. There are some species whose 
larvae occur in rotten wood and a few have a phosphorescent 
property. These are not of economic importance. 

Buprestidse.— The Buprestidce have larvae that are wood- 
boring in habit and on account of their shape — the very 
broad anterior segment of the body — are called the flat- 
head borers. Destructive species occur in maple, apple, 
hickory, and a considerable number of common trees. The 
best-known is the ilat-headed apple-tree borer {Chrysoho- 
thris femomta), which affects apple and also maple, and 
perhaps other trees. The adult is a somewhat flattened and 
elongated oval beetle with rather shallow metallic pits on 
the wing covers. They appear in early summer and will be 
found running about over the bark of the trees where the 
sun strikes them, and the eggs are deposited on rough 
spots of the bark and hatch in a short time. The larvae 
burrow just beneath the bark and burrow out a shallow cavity, 
limiting themselves to the cambium at least in the earlier 
part of their lives. The cavity eaten out may be one-half 
to three-quarters of an inch wide. The head is small but the 
first' segment of the body is quite large and flat and is per- 
haps rather naturally taken to be the head by ordinary 
observers. The remaining segments are slender and nearly 
cylindrical. It lies in the cavity in a flat position. The 
burrows never go down into the heart of the tree but they 
produce dead patches in the growing wood at the surface, 
and if they are numerous they may form a girdle and cut 
off the sap. The larvae make their growth two or three feet 
from the ground on apple trees and occur about the lower 
branches and a few may girdle the tree. The cycle of the 
species is completed in a year. The larvae burrow during 
the summer and autumn, are dormant through the cold 
weather, and pupate in the spring, the adults appearing in 
the summer. The species is usually restricted prett}' closely 
to one kind of plant. 



182 COLEOPTERA— BEETLES 

Lampyridse. — The fire-fly family is quite an exceptional 
one, and is very interesting on account of the brilliant phos- 
phorescent property. This is most commonly observed 
during June and early July and represents the time when 
the adults are most abundant. There are a number of 
species possessing the phosphorescent organs. The eggs 
are deposited and the larvse probably develop during that 
same summer, and the pupa stage is reached and adults issue 
the following season. They pupate perhaps in fall or else 
in spring. They are subterranean and are carnivorous and 
feed upon the larvse of other species. 

Lucanidse {Stag Beetles). — The lucanidse are large forms 
with very prominent mandibles which in some species develop 
into antler-like structures. The Lucanus dama larva lives 
in rotten wood, old stumps, and logs, etc., and only inci- 
dentally feeds on living wood. The larvse never start on 
living wood. The grubs are large, white, fleshy creatures 
with the body curved, almost coiled, and they pupate in the 
wood in which they are developed and the adults run over 
the ground in timber lands. The adults are quite common 
along the beach. They are not adapted for long flight. 

A quite interesting species is the horned Passalus {Passa- 
liis cornuttis) which lives in wood in almost the same manner 
as the last species, but the larva is flattened and the adult 
quite prominently flattened. The wings are considerably 
aborted and the species probably quite limited in its flight. 

Scarabseidse. — The ScaraboBidoe are characterized quite 
readily by the structure of the antennae. They have a very 
specialized form of antennae consisting of a series of small 
joints and then a broad terminal structure which is made 
up of three or five leaves folded together like the leaves of a 
book. These may be separated when the insect is flying. 
They are presumed to be the organ of the sense of smell. 
There are many sensory pits, and they give evidence of hav- 
ing strong olfactory sense, in that they collect at any decay- 
ing matter. They are not all scavengers, but they all have 
an acute sense of smell. The tumble bugs and a host of 
scavenger beetles related to it are included in this family. 



SCARAB^IDM 



183 



The Egyptian scarabs belong here. The tumble bugs 
simply enclose their eggs in little masses of refuse matter. 
This is to serve as food substance for the larvae, and they 
shape it in a ball and roll it along until it becomes coated 
with earth. The balls are finally buried in the earth. The 
eggs hatch here and the larvse develop and get their sub- 
sistence from the material in the ball. 




Fig. 130. — Corpris Carolina, under side. Enlarged. (From photo.) 



May Beetles or June Bugs. — Important economic species 
are the leaf-eating species. These are species of the genus 
Lachnosterna — Lachnosterna fusca in particular. These are 
known as May beetles or June bugs. They are distributed 
all through the country. There are perhaps twenty-five or 
thirty common species which occur in great abundance 
about the same time of the year, but these differ in minute 
characters of genitalia. They were formerly all grouped 



184 



COI.Eorr ERA— BEETLES, 



species. Tlioy are lejii'-eating in the adult 
stage. The adults ap])ear rather early in summer, May or 
June. They are destructive in the adult stage by cutting 
ofr the leaves of trees. They do not eat the leaves much 
l)ut cut them off at the petiole. Sometimes trees are 
completely stripped. They mate in the e\'ening when they 
fly in great numbers. The eggs are deposited out of doors 
and in grass land particularly. The larvae feed on grass 
roots, and if this remains available they develop there in 




Fig. 131. — The common May heQile {Lachnosterna fused): 1, the pupa; 
2, the larva or white grub in its ground cell; 3 and Jf., the beetle, side and 
dorsal views. (After Riley.) 



about three years and when they get fairly near maturity, 
about the spring of the third year, they cut off the roots of 
the grass pretty severely, sometimes cutting the turf oft' 
completely. This causes the same kind of loss as is caused 
by cut worms, grasshoppers, etc., or more severe because 
of injury below the crown. At this time they are known as 
white grubs and are similar in appearance to the larvae of the 
stag beetles. If the grass is plowed under and the field is 
planted to some other crop the grubs starve or else attack 



SCARAByEID^ 



185 



the other vegetation which sometimes suffers severely. 
Strawberry beds are quite hkely to suffer. There are no 
satisfactory' remedies. About the only thing that could be 
of much use is attention at the time of egg deposition. Appli- 
cation of kerosene has been reported in some cases as suc- 
cessful on small areas such as lawns or parts of park land. 

Rose-chafer {Macrodadyhis subspinosiis, Fab.).^ — The rose- 
chafer is a small, yellowish-brown beetle, about one-third 
of an inch in length, with very long legs. It occurs in great 




Fig. 132. — Rose-chafer {Macrodactylus subspinosus) : a, female beetle; 
b, anterior part of male; c, pygidium of male; d, abdomen of male; e, pupa; 
/, larva. All enlarged. (From Riley, Div. Ent., U. S. Dept. Ag.) 



numbers at the time of the blossoming of the garden rose, 
and will in a couple of weeks entirely strip the bushes of 
blossoms, leaves, and fruit. It also attacks the grape, 
apple, pear, cherry, peach, and other fruit trees, but is 
especially injurious to the rose and grape. 

The ravages of the rose-chafer are common in eastern 
United States and Canada. The date of the first appearance 
of the rose-chafer varies with the season but it is usually 
as early as the first of June. They begin mating imme- 



186 



COLEOPTERA— BEETLES 



diately after emerging from the ground. They continue feed- 
ing from four to six weeks and are almost constantly paired 
during this time. The eggs are deposited singly a few inches 
below the surface of the ground, each female laying from 









^KL 




WBUL-^ V ' -^'^^^l 


^^^^^ 







Fig. 133.— Rose-chafer work. (Photo from Ohio Exp. Sta.) 



twenty-four to thirty-six eggs. The larva hatches in about 
two or three weeks and begins feeding on grass and tender 
shoots. The larva is mature in the autumn and digs down into 
the earth where it builds a small earthen case in which it 



CERAMBYCIDM 187 

passes the winter, pupating in the early spring and emerging 
as adult early in June. 

There have as yet been no very successful methods of 
control discovered. Heavy spraying with arsenate of lead 
when the beetles appear will kill those feeding on the 
poisoned leaves, but if very abundant, successive attacks of 
newly appearing individuals may make this of little avail. 

The Cerambycidse. — The wood-boring beetles show quite 
a different habit from the subterranean forms. They are 
called the long-horned borers and have very long antennae 
with usually eleven joints. In the genus Prionus the number 
is greater. The length of the antennae is produced by elonga- 
tion of the joints. In some species the antennae are two or 
three times the length of the body. They are typically 
wood-boring, and all except one or two genera are borers 
in the heart- wood of woody plants. Gradations between 
leaf-feeding and wood-boring are to be seen in a few species 
that live in the pith of softer plants, and in a few that are 
borers in the roots. The extremes are perhaps to be recog- 
nized in those forms that burrow into the heart-wood of 
the hickory, maple, etc., and that live in such wood after 
it has been cut and killed. The larvae are the borers. Some- 
times larvae are found in furniture. They seem to require 
almost the minimum of moisture and of air. 

Hickory Borer {Chion cinctns). — ^The hickory borer is 
another species which attacks particularly dead or recently 
felled trees. Eggs are laid on the dead timber. The borers 
will gather in large numbers on cord wood the first two or 
three years after cutting. They sometimes make the wood 
of comparatively small value for fuel. It is useless for 
manufacturing purposes. One remedy is to use the wood 
rather promptly after cutting, within a year. Cutting in 
the fall is recommended by woodmen, also stripping bark is 
said to act as a preventative. They do not work during the 
cold weather. The adults occur onl}^ in the summer. 

Round-headed Borers {Saperda Candida). — The round- 
headed borers are among the most common pests of orchards 
and their life-cycle includes about three years. The adult. 



188 



COLEOPTER A— BEETLES 



wliicJi is brown with two conspicuous wliite stripes, appears 
in early summer, ]May or June, deposits eggs at the lower 




Fig. 134. — Chion cinctus: a, eggs, natural size; b, egg, enlarged; c, 
larva; d, pupa; e, adult male; /, antennae of female. (After Osborn, 
in Garden and Forest.) 

part of the trunk, near the ground. The larvae on hatching 
burrow into the tree and for the first season live near the 
bark, then they burrow down and pass the winter in the 




Fig. 13.'i. — Work of hickory borer, showing longitudinal and cross- 
section of stick with burrows. One-half natural size. (After Osborn, in 
Garden and Forest.) 



lower part of the burrow^ perhaps below the surface of the 
ground. The next two summers are spent in boring upward 



CERAMBYCIDyE 



189 



and inward to the heart of the tree and then boring toward 
the surface, leaving only a thin layer of bark. Before pupat- 
ing the larva packs the burrow with chips, then withdraws 
a little from the surface to pupate. The fully grown larvse, 
pupa3, and adults may all be found in the spring of the same 
year. All mature and become ready to deposit eggs about 
June. The adult has simply to work its way through the 
thin packing of chips and a little bark to reach the surface. 
It does no real boring in the wood. Few of the species 
have the abilitv as adults to cut awav the heart- wood. 




Fig. 136. — Saperda Candida: a, larva, from side; h, from above; c, 
female beetle; d, pupa. All enlarged one-third. (After Chittenden, Div. 
Ent., U. S. Dept. Ag.) 



There are two means of control. One is to protect the 
trunk of the tree by means of applications of alkali washes, 
paint, etc., to prevent the depositing of eggs. Barriers 
placed around the trunk are used, such as wire netting, tarred 
paper, and building paper, or even several thicknesses of 
newspapers. Where such material is used it is better to 
remove it later in the season (by September first) to give 
the bark its normal exposure. Another way is to cut out the 
larvse in the autumn of the first season; the burrow close 



190 COLEOPTERA— BEETLES 

to the bark can be found by means of the chips tliat are 
forced out and project from the burrow or drop tp the 
ground and form little piles. The grub can be cut out with 
a clean sweep of the knife and the wound covered with a 
little wax, thick paint, or something of the kind to prevent 
entrance of water and formation of decaying spots. 

Leaf Beetles {Chrysomelidce). — The leaf beetles represent 
rather more primitive habits and have rather more primi- 
tive characters than CeramhycidcB, the antennae being short 
and filiform, but are similar in the character of the tarsi. 
The larvse of ChrysomelidoB with a few exceptions feed on the 
leaves of plants in a very exposed manner and the adults 
feed, so far as they feed at all, on the leaves of different kinds 




Fig. 137. — Colorado potato beetle (Leptinotarsa decemlineata) : a, beetle; 
h. larva; c, pupa. Enlarged. (Chittenden, Div. Ent., U. S. Dept. Ag.) 

of vegetation. They are sometimes restricted to certain 
plants and sometimes have a variety of hosts. 

The Colorado potato beetle {Leptinotarsa decemlineata) 
was at one time a much-dreaded pest but can now be easily 
controlled. It occurred originally in the Rocky Mountain 
region, feeding on wild plants related to the potato, but with 
the introduction of the potato and abundance of food it 
multiplied rapidly, migrated eastward and soon spread over 
the entire country. It has two generations each year, adults 
hibernating in the ground, appearing in early spring and 
laying eggs on first-appearing potato vines. The larvae 
which hatch soon feed on the leaves, maturing in a short 
time, pupating under ground, and a summer generation of 



CHRYSOMELIDJE 



191 



beetles appears in midsummer. These lay eggs, and larvae 
may be very abundant in late summer, pupate in early fall, 
and give rise to beetles that hibernate. Spraying with 
arsenical solutions is effective in their control. 

Agriculturally a little group of beetles, the Diabrotica, 
are very important. They present an exception to the gen- 
eral habit of the family in that they attack roots under the 
ground. There are three species of interest. The best- 
known species is the striped squash beetle ( Diabrotica 




Fig. 13S. — Striped cunumber beetle (Diabrotica Httaia): a, beetle; 6, 
larva; c, pupa; d, egg; a, h, c, much enlarged; d, more enlarged. (After 
Chittenden, Div. Ent., .U. S. Dept. Ag.) 



vittata), a pest to squashes and melons, which is an extremely 
well-known species. It feeds on stems and leaves close to 
the ground and, as larva, in the young squashes, and per- 
haps represents the intermediate stage between stem and 
root-feeding species. 

Diabrotica longicornis, the corn-root worm, is distinctly 
a root-feeding species. The beetle appears in late summer 
and autumn and is a rather bright green little beetle with 
no markings. It is found in late summer on the corn stalks, 
on the fall flowers, such as asters, sunflowers, goldenrod, 



192 



CO LEO I' 1 'ERA —BEE 7 'LES 



etc., and feeds perhaps on the pollen of tliese flowers. In 
some cases it is quite remote from the corn fields. They 
deposit eggs in the ground. The eggs remain over winter 
and hatch the following spring shortly after the corn begins 
to grow, and the larva commences feeding on the corn roots. 
While the roots are small they commence at the end and 
work along the root; after the roots are larger they work 
into the roots. They cause the ears to be small and when 
numerous can kill out the entire plant. They get their 
growth by the middle of July or first of August, pupate, 
and spend a few days in the pupal stage, and issue as adults 




Fig. 139. — "Western corn-root worm (Diabrotica longicornis) : a, beetle; 
h, larva or root worm; c, enlarged leg of same; d, pupa — all enlarged; 
c, more enlarged. (Chittenden, Div. Ent., V . S. Dept. Ag.) 



in autumn. There is a single brood in a year. Rotation of 
crops serves as an almost absolute means of prevention of 
injury from this species. It was most troublesome in the 
corn regions of Illinois where corn was planted year after 
year on the same ground. 

The other species with this habit is also destructive to 
corn ( Diabrotica \2-yunctata) . It is known as the Southern 
corn-root worm. It is also troublesome to some other 
plants, so that its control is not so easy or certain. 

The elm-leaf beetle, an introduced species which has been 
a very serious pest in the Atlantic States, has recently 



FAMILY BRUCHID^ 



193 



occurred in Ohio. It has worked westward from some 
infected centre in the east, and is apparently spreading over- 
the country in general. 

The cucumber flea beetle and grape-vine flea beetle also 
come in this group. 

Family Bruchidse. — The family Bnichidcp in some respects 
approaches very near the snout beetles. This includes the 
pea and bean weevil and the species are essentially seed- 




FiG. 140. — Southern corn-root worm (Diahrotica 12-punctata) : a, beetle; 
b, egg; c, larva; d, anal segment of larva; e, work of larva at base of corn 
stalk; /, pupa. All much enlarged except e, which is reduced. (After 
Riley, except/, after Chittenden, Div. Ent., U. S. Dept. Ag.) 

eating forms. In case of the pea weevil the eggs are laid 
out of doors on growing pea pods and they burrow into the 
pod and get into the growing peas, usually one to each pea. 
They grow with the growing pea and remain in the pea to 
pupate and then later the adults are found in stored peas 
in winter and spring. Immense numbers of these larvae 
are destroyed by the eaters of green peas but the species 
holds its own. It does not become noticeable except in 
stored peas. The larvse at the time of green peas are small 
13 



194 



COLEOPTERA— BEETLES 



and soft, probably of a good flavor like the pea, and do not 
attract any attention at all. The way of preventing its 
occurrence is to pick out the infested peas and treat them 
before planting. Soaking in cold water for several hours 




Fig. 141. — Elm-leaf beetle (Galerucella lufeola): a, e, eggs; 6, g, larvae; 
c, k, adults; /, sculpture of egg; /i, side view of segment of larva; i, dorsal 
view of same; j, pupa; I, portion of elytron of adult; a, b, c, natural size; 
0, j, k, somewhat enlarged; e, h, i, I, much enlarged; /, highly magnified. 
(From Riley, Div. Ent., U. S. Dept. Ag.) 



kills the adults and prevents egg deposition. Warm water 
may be used and will hasten the death of the larva but it 
must not be so hot as to kill the germ. Buggy peas will 
germinate usually just as readily as the sound ones but 
have less material to grow on. Peas that are kept in bins 



RHYNCOPHORA 



195 



or sacks where the adult cannot get out can do no harm to 
the new fields. Fumigation of the seed is one method of 
destroying the beetles. In some places it is required by law. 
The Rhyncophora or snout beetles are distinguished by 
the elongate head drawn out into a narrow and sometimes 




Fig. 142. — The clover-leaf weevil (Phytonomus punctatus): a, egg; 
b, b, b, b, larvae feeding; c, recently hatched larva; d, head of same from 
beneath; e, jaw of same; /, cocoon; (7, meshes of cocoon; /i, pupa; i, beetle; 
j, same in outline; k, same dorsal view; I, tarsus of beetle; tn, antenna of 
same; b, f, i, natural size; others more or less enlarged. (From Riley, 
Div. Ent., U. S. Dept. Ag.) 



very long "snout" ai the end of which the minute mouth 
parts are attached. The larvse are commonly found as 
grubs in seeds, nuts, etc., but the clover-leaf w^eevil and the 
alfalfa weevil feed upon the leaves and stems of clover and 
alfalfa. 



196 



COLEOPTERA— BEETLES 



Plum Curculio {ConotrachcJvs iiennyhar, Horbst.). — This 
pest is still one of the main difficulties in the way of raising 
good crops of plums, but it may be considered at least pos- 
sible, by proper care, to secure good crops of perfect fruit. 
The beetles hibernate and appear on the trees shortly after 
bloom, feeding to some extent on the leaves and young 
fruit, and then laying their eggs in the young plums, the 
punctures indicating point of deposition being marked with 
a crescent-shaped cut. The larvae burrow through the pulp 




Fig. 143. — The larger chestnut weevil (Balaninus proboscideus) : a, 
female beetle; b, same in outline from side; c, head, rostrum, and antennae 
of male. Three times natural size. (Chittenden, Div. Ent., U. S. Dept. 
Ag.) 



of the plum, not entering the stone. The infested fruit 
ripens prematurely and falls from the tree, and the larvse 
for the most part leave the plums and pupate under ground. 
The adult beetles appear in late summer or early autumn 
and live over till the following spring. 

The beetles drop readily when disturbed, and the well- 
known plan of jarring trees daily during the time of egg 
deposition in the morning and gathering the beetles on can- 
vas spread under the trees is a valuable means of preventing 



RHYNCOPHORA 



197 



their injuries. Spraying with an arsenical solution has 
been found to be useful, and if the plum trees are thoroughly 
sprayed once soon after the bloom has fallen and again ten 




Fig. 144. — Larger chestnut weevil (Balaninus proboscideus) : a, larva; 
b, c, female pupa; d, eggs. All enlarged. (Chittenden, Div. Ent., U. S. 
Dept. Ag.) 





Fig. 145 Fig. 146 

Fig. 145. — Balaninus proboscideus: head of larva, much enlarged. (Chit- 
tenden, Div. Ent., U. S. Dept. Ag.) 

Fig. 146. — Pecan weevil (Balaninus caryce): a, female, dorsal view 
6, same, lateral view, in outline; c, head with rostrum and antenna of male. 
About two and one-half times size. (Chittenden, Div. Ent., U. S. Dept. 
Ag.) 

days later, it will greatly help in securing perfect fruit. 
Some experiments have shown extremely valuable results 
in this direction. 



198 



COLEOPTERA— BEETLES 



The nut weevils have enormously elongated snouts. 
They infest chestnuts, pecans, acorns, hazel-nuts, etc. 




Fig. 147. — Hazel-nut weevil {Balaninus obtusus) : a, adult female, dorsal 
view; 6, head from side; c. head of male from side. Enlarged. (Chittenden, 
Div. Ent., U. S. Dept. Ag.) 




Fig. 148. — Boll weevil (Anthonomus grandis): a, adult beetle; h, pupa; 
c, larva. All enlarged. (From Howard, Div. Ent., U. S. Dept. Ag.) 



Cotton-boll Weevil. — In the Southern States we have a 
most striking case of introduction and dispersal in the 
cotton-boll weevil, which came into southern Texas from 
Mexico about the year 1890 and has been making steady 




-30 

o 

C 



200 



COLEOPTERA— BEETLES 



progress throiigliout tlie cotton-growing States. It is a small 
beetle somewhat like the clover wee\'il but restricted to the 
cotton plant for its food and for the early stages is restricted 
to the bolls of cotton for its particular food. This means 
that it can develop only in places where cotton grows and 
at such time as the cotton bolls are in process of develop- 
ment. This species has practically revolutionized the agri- 
cultural conditions of the Southern States in which it has 
spread, and it is unnecessary to say that it must have had 






Fig. 150. — White-pine weevil (Pissodes strobi): a, adult, smaller figure 
natural size; b, larva, line at left natural length; c, pupa, small figure of 
adult showing natural size. (Hopkins, Div. Ent., U. S. Dept. Ag.) 



a very pronounced influence upon the other kinds of insects 
or animals that occur in that region. 

The map illustrates its progress from year to year and it 
is a matter of considerable interest and significance that 
the northern border of its distribution has remained inside 
the possible area of cotton growth. It may also be noticed 
that this line agrees remarkably for the northern distribu- 
tion of the cattle tick and other insects which are of tropical 
derivation. 



RHYNCOPHORA 



201 




Fig. 151 




Fig. 152 



Fig. 153 




Fig. 154 



Fig. 151. — Hylastinus obscurus: adult insect — natural size at right. 
(Webster, Div. Ent., U. S. Dept. Ag.) 

Fig 152. — Hylastinus obscurus: larva or grub — much enlarged. (After 
Webster, Div. Ent., U. S. Dept. Ag.) 

Fig. 153. — Hylastinus obscurus: pupa — much enlarged. (After Webster.) 

Fig. 154. — Clover root, showing work of Hylastinus obscurus. Slightly 
enlarged. (After Webster, Div. Ent., U. S. Dept. Ag.) 



202 



COLEOPTERA— BEETLES 





Fig. 155. — Scolytus rugulosus- o, beetle; b, same, in profile; c, pupa; 
d, larva. All magnified about ten times, (Bur. Ent., U. S. Dept. Ag.) 




Fig. 156. — Scolytus rugulosus. Section of injured tree. (Photo from 
Ohio Exp. Sta.) 



RHYNCOPHORA 



203 



The insect hibernates as an adult and may be carried by 
shipments of cotton seed or other objects. The eggs are 
laid on cotton bolls in early summer and the larvse feed 
within the bolls, ruining the fibers that would form the 
crop. 




Fig 157.— Dendroctonus valens: adult. (A. D. Hopkins, Bur. Ent., 
U. S. Dept. Ag.) 

Diversified farming, the clearing up and burning of old 
cotton plants in the fall and early planting are some of the 
measures used in efforts to control the species. 

The white-pine weevil is a destructive species m the pnie 
forests of the Northern States and Canada and occurs south- 
ward along the Allegheny range to North Carolma. 

Scolytidse or Engraver Beetles and Bark Beetles.— ihese 
are interesting because of their forming characteristic mark- 



204 



COLEOPTERA— BEETLES 



ings between tlie bark and the wood. They are a great 
economic pest in forests. The pine forests of Virginia, 
Georgia, etc., and the Black Hills have been greatly injured. 




Fig. 158. — Dendroctonus valens: work in bark at base of stump: a. en- 
trance and pitch tube; b, egg gallery; c, boring dust and resin; d, pupal 
cell; «", pupa: /, larvae at work feeding on inner living bark; (7, exit burrows; 
h, resulting old scar or basal wound, often referred to as basal fire wound; 
i, inner bark with outer corky bark removed. (A. D. Hopkins, Bur. Ent.. 
U. S. Dept. Ag.) 



RHYNCOPHORA 205 

One of the destructive species {Hylastinvs obscurus) is a 
borer in the roots of clover and occasions much injur}^ to this 
crop. 

Fruit-tree Bark Beetle (Scolytus rugulosus). — The fruit-tree 
bark beetle is a common pest of orchard trees and the cause 
of much injury. Its work becomes apparent in numerous 
small round holes in the bark. Shot-hole borer is one name 
for the species, based on this feature. 

The species of Dendroctonus are mainly destructive to 
forest trees, and are responsible for extensive inroads on 
our forest resources. 



CHAPTER VIII. 

LEPIDOPTERA. 

The Lepidoptera form one of the largest orders of insects 
including a great number of subdivisions and including 
some of the most brilliant forms and some of the extremes in 
size — moths, butterflies, etc. They are separated from all 
other insects by the mouth structure, it being adapted for 
lapping up nectar of flowers and this structure being devel- 
oped largely from the maxillae, the parts being elongated 



,., MESOTHOfiAX\ 

ABDOM£N MerATHOMX \ \ 




TnoOKtCLEG' 



Fig. 159. — Tomato worm (larva of Phleqethontius 5-maculata), showing 
structure of lepidopterous larvae. (Drawn by J. I. Hambleton.) 

and extended for some length when in use and when not 
in use folded up like a watch spring. Some forms have 
remnants of rudimentary mandibles but in most cases these 
cannot be found. When they occur the mouth parts seem to 
be in their general structure related to the Trichoptera.' 
The larvae are all mandibulate. Another distinctive character 
is the complete covering of body and wings with minute 
scales. 

The Lepidoptera show quite extreme condition in meta- 
morphosis. The larvae are known as caterpillars. They 
( 206 ) 



BAG-WORM MOTHS 



207 



usually have a series of prolegs or false legs developed on 
the abdominal segments. The more common number is 
ten, four pairs located on the central abdominal segments 
and one terminal pair. These are not homologous with the 
segmentally jointed appendages of insects generally. They 
stand out prominently and are fitted commonly with rows 
of small hooks or teeth at the margin. The larvse are elon- 
gate and generally cylindrical and are followed by a pupa 
stage strikingly different from the larval stage and fre- 




FiG. IGO. — Bag worm (Thyridopteryx ephemerceformis) : a, full-grown 
larva; h, head of same; c, male pupa; d, female pupa; e, adult female; 
/, adult male. All enlarged. (From Howard, Div. Ent., U. S. Dept. Ag.) 



quently enclosed in a cocoon. This is a quiescent stage. 
The adult on issuing splits the pupal case along the dorsal 
portion and crowds its way out. 

Bag-worm Moths. — Among the lower forms are the bag- 
worm moths. These are forms in which the larvae construct 
a case or bag of bits of leaves or twigs with which to protect 
themselves. Almost parallel with the habit of the caddice 
flies. One of the most common is the evergreen bag worm 
{Thyridopteryx ephemercEformis) . Its favorite fqod plants 
are conifera, red cedar, and arbor vitae. It occurs com- 



208 



LEPIDOPTERA 



monly over a large ])()rti()n of eastern United States. The 
bags which are formed by this insect are found abundantly 
in autumn and mnter and early spring attached to the 
trees upon which they have developed. They may crawl 
some little distance from the trees and attach themselves to 
some other object. Each bag is made up of numerous bits 
of leaf and twig, making a regular structure. These bags 
in late summer and autumn furnish protection for develop- 




FiG. 161. — Bag worm (a, b, c) at successive stages of growth: c, male 
bag; d, female bag. Natural size. (From Howard, Div. Ent., U. S. Dept. 
Ag.) 



ment of the adult. The females remain within the bag. 
They are wingless and grub-like with very large bodies. 
The males issue from the chrysalis and fly about with well- 
developed wings. After fertilization the females deposit 
eggs within the bag, filling the cavity of the bag with a mass 
of eggs. This forms the protective covering for the egg 
mass during the winter. The eggs hatch in the following 
season and the larvae begin feeding upon the foliage of the 
tree and begin the construction of a case or bag almost as 



BAG-WORM MOTHS 



209 




Fig. 162. — Bag worm {Thi,ridopieri]x ephemerceformis) cases from 
cedar tree. 
14 



210 LEPIDOPTERA 

soon as they begin to feed. The bag is made of silk mixed 
with the bits of leaf, etc., and attached to the twig by silken 
threads. The metamorphosis to the pupal stage occurs 
within the case. There is a marked difference in the size, 
etc., of the males and females in the case. They are a 
source of injury to evergreen trees, stripping the foliage. 
They are a little difficult to contend with. Applications 
of poisonous arsenical solutions to the foliage where they 
are feeding will kill them. The cocoons may be gathered 
and destroyed. The migration from tree to tree is limited 
by the migration of the larvse, as the females remain in the 
bag and do not travel about. The migrations of the cater- 
pillars are limited to rather short distances. This is the best- 
known species of the family. 

Family Cossidse.^The family Cossidce is another group 
presenting adaptations to special food and includes the 
carpenter moths — characterizied by the wood-boring habit 
of the larvae. This is a decided departure from the leaf-feed- 
ing habit. The leaf-feeding habit is the most primitive 
condition. They burrow into the heart-wood of various 
trees. 

Locust-tree Borer {Prionoxystvs robinice). — The locust-tree 
borer is the most conspicuous. It occurs in other trees 
besides the locust. The moths are strong-bodied and 
resemble the hawk moths in the shape of the body and in the 
narrow form of the wings. The adults appear in June and 
July and deposit their eggs upon various trees and the larvae 
on hatching begin burrowing into the tree, living at first 
in the cambium and then burrowing deeper into the woody 
tissue. The larvae are supposed to require three years for 
their growth. The larva is whitish and almost naked with 
only a few scanty, minute hairs and looks more like the 
grub of a beetle than like a caterpillar of a moth. It forms 
a rather large tunnel, the burrow when the larva gets full 
size being about one-half inch. These burrows frequently 
permit the entrance of moisture and so start decay and in 
many cases cause some distortion; they cause trees to break 
easily. Before changing to the pupal stage they bore out to 



FAMILY PYRALID^ 211 

the bark, leaving only a thin layer that has to be pushed off 
by the pupa before issuing as a moth. 

In another family, PyralidoB, there is one species, the 
clover-hay worm {Pyralis costalis), which is very destructive. 
They injure the stored crop of clover. The moths of this 
species appear in summer, perhaps most abundantly about 
midsummer. Eggs are deposited largely in the newly stored 
hay and the larvse feed upon this hay. Perhaps the majority 
continue their larval life through the winter— the hay 
becomes matted and filled with the silken webs they spin 
and with the black gunpowder-like excrement they discharge. 




Fig. 163. — Indian-meal moth {Plodia inter pundella) : a, adult; b, pupa; 
c and/, larva; d, head; e, first abdominal segment of larva. All enlarged. 
(After Chittenden, Div. Ent., Bui. 4, n.s., 1896, U. S. Dept. Ag.) 

The hay, while not all consumed, thus becomes unfit for stock 
food. They get their growth in the hay and change to 
chrysalids and the adults issue and fly about in hay mows 
and about hay stacks. 

Closely related is a species known as Pyralis farinalis, 
which feeds upon stored grain and also upon clover hay. 
The life-cycle is about the same as of the other species. 

Indian-meal Moth (Plodia interimnctella) . — This is another 
common pest of food substances. It occurs in somewhat 
the same materials as the saw-toothed beetle. It is quite 
different, however, the adult being a small moth somewhat 
similar to the clothes moth in appearance, although larger. 



212 



LEPIDOPTERA 



The eggs are laid in tlie ^'arious food substances, breakfast 
food, seeds, dried fruits, etc., and the larva which is a small, 
slender caterpillar feeds in this material and usually spins a 
web as it works so that the food is made quite undesirable. 
There are usually two broods each year in the latitude of 
Ohio, but with warmth, the number of generations may be 
increased to four or five. As with the preceding species, it 
is possible to sift out the insects from the flour or meal but 
if infested to any extent their presence is undesirable and 
infested packages are best returned to the grocer to exliange 
for fresh material. The prevention of their entrance into 
the packages of breakfast foods, etc., should be attended 
to at the mills or packing houses. 




Fig. 164. — Mediterranean flour moth {Ephestia kuehniella): a, moth; 
b, the same from side, resting; c, larva; d, pupa; e, abdominal segments 
of larva; a and d, enlarged; e, more enlarged. (After Chittenden, Div. 
Ent., Circ. 112, U. S. Dept. Ag.) 



The direct treatment of these insects in stored products 
where fumigation is possible is in store rooms, but cannot be 
done as advantageously as in the mills or warehouses or 
where the cereals are prepared. 

The Mediterranean Flour Moth {EpJwstia kuehniella). — 
This is a destructive insect, occurring in stored wheat and 
other grains, and particularly in mills and warehouses, and 
has now been distributed over all parts of the world where 
grains and their products are stored. It is one of the most 
serious pests in the large flour mills of the northern United 
States, in some cases clogging and stopping the machinery 



BEE MOTH 213 

and causing a considerable loss in the flour, meal, or other 
products. Its life-cycle is fairly continuous where buildings 
are warm enough to permit its growth. 

The principal methods of control are by means of heat 
and fumigation. Where a heating system is present, and it 
is possible to raise the temperature of the building to 125°, 
this is a most eft'ective plan and requires but a short suspen- 
sion of the operations of the mill. Where this is not avail- 
able the use of hydrocyanic gas or bisulphide fumigation is 
necessary, although frequent cleaning of the building and 
the careful disposition of insects which are found in the 
accumulated dust in different parts of the building will serve 
to keep them in check. 

Bee Moth {GaUeria melloneUa). — The bee moth gets its 
name from the fact that it lives in the hives of honey bees. 
It is confined closely to this habit and all stages will be 
found in and around the hives. The adults are found 
during the summer months particularly and are com- 
monly hidden under and around the hives, and if disturbed 
tend to slip away, crawling into corners or making a 
short flight to some safe place, almost as slippery as cock- 
roaches. They gain entrance to the hives by slipping in at 
the entrance, especially if the entrance is not well guarded, 
they deposit eggs upon the comb doubtless in some corner 
where the bees are not numerous. The larvse feed upon the 
wax and make long burrows around through the combs. 
According to Comstock, the larva feeds only at night and 
hides in its burrow during the day. They pupate generally 
within the hive and upon the tops of the frames or in 
the corners, and in some cases probably creep outside and 
get underneath the hive. They spin quite a tough silken 
cocoon within which they pupate. This stage gives rise 
later to the moth. There are at least two generations 
during the season. The first measure in the way of pre- 
vention is to keep the colonies in good condition and a part 
of the treatment may consist in looking over colonies and 
catching and killing any moths, larvse, or pupae that may be 
observed. 



214 LEPIDOPTERA 

Close-wings (CramhicJcr). — The close-winfi^s are named 
from the i)()sitic)ii of the wings, which are folded down very 
closely at the sides of the body and in many cases they 
fit so close to the stem on which they rest that the moth 
is completely hidden. Many of them are light yellowish 
and straw-colored which blends quite well with the color 
of the straw or grass on which they rest. The genus 
Crambus includes fifty or sixty species, and most of them are 
grass-feeding species that are to be considered as distinct 
pests in pastures and meadows, though they only now and 
then multiply in such numbers as to attract uni\ersal atten- 
tion. These different species present different life histories 
and these must be known in detail in order to treat them 
intelligently. The most abundant species in the Mississippi 
valley has the following life-cycle. The sod worm occurs in 
the adult stage about the latter part of May or the first 
of June and sometimes in very great abundance. They are 
attracted by light. They deposit eggs at the times of flights 
and normally deposit these over grass lands, and the eggs 
are evidently scattered very generally and are extruded 
singly, evidently with some force. They drop into the grass 
and on the surface of the ground, and the larvae when hatched 
feed at or near the surface or burrow a little below the 
surface of the ground and form a silk-lined tube in which 
they live and are protected mostly during the daytime, 
coming to the surface at night to feed upon the fresh leaves. 
Injthis way they cut grass off very near the surface of the 
ground'and it falls down and dries up, and is lost for hay and 
pasturage. The plants are not killed outright. The effect 
is similar to that of close pasturing of cows or sheep. If 
the insects eat down into the ground the grass may be 
killed. They attain their growth in the course of about four 
or five weeks and pupate in August and the second genera- 
tion of moths appears during the middle or latter part of 
August. These may occur in large numbers if the season 
is favorable. These deposit eggs and the larva? from these 
begin feeding in autumn and become partially grown but 
do not mature, remaining in the larval stage over winter. 



FAMILY TORTRICIDjE 215 

In the following spring they finish their growth, pupating 
and issuing as moths in the latter part of May or early part 
of June. If the grass land is plowed and another crop put 
on it, especially corn, the crop may suffer very severely. 
The remedy is to plow the ground early enough in autumn 
to prevent egg deposition. If plowed in the spring, it should 
be plowed early. They are attracted very generally to light 
and trap-lights in fields ought to be very useful. In Iowa, 
where ground squirrels (13-striped squirrels) are common, it 
was noticed that the pupae of these sod worms are eaten by 
the squirrels. They are also parasitized, and this would 
perhaps help to keep them reduced in numbers. 

A species with a remarkably different food habit lives on 
the maple scale (scale insects) Coccid-eating. 

Family Tortricidse. — This family includes the leaf-rollers 
and bud moths. These are characterized by a broad form of 
the wing and are distinctly opposed to the slender, narrow 
wings of the Crambus. The costa is very strongly curved. 
The mouth parts are not Very conspicuous; head small. The 
larvse are mainly leaf-rollers and inhabitants of the buds 
of different kinds of plants. These forms have several 
injurious species. Cacaesia roseana is quite common and 
troublesome to florists and rose growers. The insects 
appear very early in the season. The larvse begin to work 
soon after the leaves have begun to unfold. The leaves will 
be tied together and the larvae w^ork within this protection 
and eat away the tissues of the leaf. In some cases they 
burrow into the opening buds and destroy the blossoms. 
They attain their growth rather rapidly and form a chrys- 
alis often in the leaves they have tied together and from 
this the moth issues. 

Codling Moth. — The worst pest in the group is the codling 
moth (Carpocapsa pomonella). This causes enormous 
losses to the orchard industry; millions of dollars being 
lost each year. Its life history is well known and can be 
found in almost any work on orchard insects, but stated 
briefly, consists in a spring brood of insects appearing and 
laying eggs shortly after apple bloom, a first brood of larvae 



216 



LKPJDOPTERA 



is found in early summer, pupation in early July, second 
brood mates about Au<^ust first, and second brood larva' 







^^Hs « jJ^;- Jtf€'' *''^H 


wSm 




Wwk 


1 



Fig. 165. — Codling moth {Carpocapsa pomonella) : larvae in cocoons upon 
bark of apple tree. (Photo by Ohio Exp. Sta.) 




Fio. 166.— Spraying for Codling moth (Carpocapsa pomonella). 
(Photo by Ohio Exp. Sta.) 



FAMILY TORTRICIDM 217 

in fall and early winter. The essential basis for treatment 
lies in the time and place of egg deposition. The egg is 
deposited in the calyx of the fruit and the larva burrows 
into the fruit. 

The whole secret of destroying the species is to have the 
poison applied placed so that it will get into this particular 
part of the apple and be there when the larva takes its first 
meal. Proper application of arsenical solution w^ill prevent 
95 to 98 per cent, of the injury. Application should be 
made very soon after the bloom falls while the fruit is still 




Fig. 167. — Codling moth (Carpocapsa pomonella) : young apples in 
condition for spraying. (Photo by Ohio Exp. Sta.) 



open at the calyx end. There are two broods in a season, 
The larvse seen in the apples in the winter are the ones from 
the second brood. They escape from the apples when 
stored and secrete themselves about the bins and change to 
pupae, and the moths are ready to issue early in the spring. 
The insects may be captured as pupse at the end of the first 
brood so as to prevent the issuing of the midsummer moths. 
This may be done by means of bands around the trees 
under which the larvae will crawl to pupate. These bands 
may be examined every few days and the pupa^ crushed. 



218 



LEPIDOPTERA 



The process is somewhat slower and less effective than spray- 
ing and is now seldom used. 




Fig. 168. — Codling moth {Carpocapsa pomonella): apples too late for 
spraying. (Photo by Ohio Exp. Sta.) 



A closely related insect, Carpocapsa saltitans, is the basis 
for the popular phenomenon known as jumping beans, 



FAMILY TORTRICID^ 219 

occurring in beans and some other seeds and causing these 
seeds to jump about in a very pecuhar manner. This is 
caused simply by the jerking movements of the body of the 
caterpillar within the seed. 

Clover-seed Caterpillar {GrapJiolitha inter stinctana, Clem.). 
— The clover-seed caterpillar is often a serious pest to the 
clover seed. Its work, however, is not confined to the seed, 
but extends to the leaves, stems, or crown, so that on the 
whole its capacity for mischief is very great. 




Fig. 169. — Codling moth {Carpocapsa pomonella) : egg. 

The moths are very small and may be generally described 
as dark brown or nearly black in color. The wing expanse 
is from 0.31 to 0.36 of an inch. The majority are marked 
by two small parallel, excurved, short, silvery lines at the 
middle of the hinder border of each forewing so that when 
the wings are closed the lines form a double crescent over 
the back. (See Fig. 167, c and d). Some, however, are found 
to have all traces of the crescents obliterated. Eight white 
silky lines are disposed along the front border of each of the 
forewings, which in common with the hindwings are deli- 
cately fringed. The wings beneath are shining and silky and 
have a greenish tinge in certain lights. 



220 LEPIDOPTERA 

The larva (Fi**-. 17(),(^/) is a small greenish-white caterpillar 
with a (lark brown head, and is al)()ut ().2r) to 0..'^ of an inch 
long when full grown. Many of them become tinged with 
red toward the hinder extremity as they approach the time 
of pupating. 

The delicate white silken cocoons are spun in the liead 
among tlie dried florets, grass, and bits of eroded but im- 
devoured flowers, so covering them with brown as to make 
them difficult of detection. The pupae work their way 
entirely out of their cocoons and drop to the ground before 
bursting their pupal cases, which may be found in abundance 
on the ground from which a brood has just issued. 




Fig. 170. — Grapholitha inter stinctana: a, larva; h, pupa; c, adult; 
all enlarged; d, adult — natural size. (After Osborn.) 

The remedies for the species are summed up as follows: 

1. Rotation of crops, not keeping clover on the same 
ground over three years, and only two if the field becomes 
badly infested. 

2. That the seed for a new crop be planted on land as 
remote as possible from old clover fields. 

3. That infested fields from which seed is desired the 
following year be pastured in the fall to take up all late 
growths and leave the field free from vegetation, and that 



FAMILY TINEIDM 



221 



no manure be applied at the time to furnish places for the 
larvae to hibernate. 

4. That clover infested during the spring be cut as early 
as practicable, while the larvae are in the heads, handled as 
carefully as possible to prevent shaking larvae from the 
heads and stored in stacks or barns, the larvae being found 
to perish under such treatment. 

5. When ready to change from clover to another crop 
plow under some time in October, November, or in early 
spring burying the larvae as deeply as possible, and roll or 
harrow to pack the surface. 

Several pjarasites have been reared which will assist in 
reducing numbers under ordinary conditions. 




Fig. 171. 



-Tinea pellionella: adult; larva; larva in case — enlarged. 
(From Riley, Div. Ent., U. S. Dept. Ag.) 



Family Tineidse. — The family Tineidce includes very 
minute moths which have slender wings and usually with 
the wings very broadly fringed, and is a specialization or 
modification from the typical broader wings. They are 
very delicate, mostly very minute and the more abundant 
outdoor forms are leaf-miners, the larvae living between the 
epidermal layers of the leaf and feeding upon the pulp of 
the leaf. Some form galls. The tough part of the leaf is 
protective at least to a degree. Some also construct cigar- 
shaped cases and are known as case-bearers. The best- 



222 



LEPIDOPTERA 



known species arc tlic clothes moths, and they have quite a 
speciahzed food habit, being Hmited to dry woolen fabrics 
or furs. There are three common species, one the case- 
bearing clothes moth, one a naked species, and one the 
carpet moth which constructs a sort of burrow within the 
goods. The life histories are similar, adults appearing in 
spring or summer and the larvae feeding in the carpets 
clothing or furs, especially during the summer months. 
Naphthaline or "moth balls" are a good repellent, cold 
storage and storage in moth -tight paper cases are helpful. 




Fig. 172. — Tineola biselliella: moth, larva, cocoon, and empty pupa 
skin — enlarged. (From Riley, Div. Ent., U. S. Dept. Ag.) 

Sesiidae. — These have a rather unusual condition for the 
Lepidoptera. In many the scales are wanting and the wings 
look glassy — like wasps' wings. Scales will usually be found 
on the veins of wings and on the body and legs, those on 
the legs -being quite large. They fly in daylight rather 
than at night and there are a number of distinctly economic 
species. The larvse are borers and live in the wood of trees 
and sometimes of annuals. The squash-vine borer is often 
very destructive to squashes, melons, and pumpkins. 

One of the most common and destructi\'e is the peach-tree 
borer {Sa7ininoidea cxitiosa). This causes serious damage to 
peach orchards in the Eastern Central States and southward. 
The adults vary a great deal in the two sexes. The females 
are larger and a darker steel-blue with a broad orange-yellow 



SESIIDJE 



223 



band about the middle of the abdomen. The males are 
banded dark and yellow with wings more glassy and body 
more slender and considerably smaller. They appear in the 




Fig. 173. — Squash- vine borer (Melittia satyrinifonnis) : a, male moth; 
h, female, with wings folded at rest; c, eggs shown on bit of squash stem; 
d, full-grown larva, in situ in vine; e, pupa; /, pupal cell. All one-third 
larger than natural size. (From Chittenden, Div. Ent., U. S. Dept. Ag.) 




Fig. 174. — Sanninoidea exitiosa: 
full-grown larva; d, female pupa; 
extruded from cocoon. 
Dept. Ag.) 



a, adult female; h, adult male; c, 

e, male pupa; /, pupa skin partially 

All natural size. (After Marlatt, Div. Ent., U. S. 



adult stage in midsummer, largely in late July or August, 
and deposit eggs near the ground around the trunks of 
peach trees and also plum, cherry, and other stone fruits. 



224 LEPIDOPTERA 

Tlie eggs are deposited in crevices or broken places on the 
bark. The great majority are within six or seven inches 
of the ground. The larvae soon hatch and bore into the bark 
and into the soft sap wood. They live close to the bark for 
a good share of the time. In some cases they are almost 
exposed. They do not seem to have developed the habit 
of boring so deeply as some others. During the autujnn 
they continue this boring, growing somewhat, and hibernat- 
ing in the larval stage. They go as deep as possible in the 
winter. In the spring they continue feeding and extend 
the l)urrows and complete their larval growth in late spring, 
mostly during May. They pupate within the burrows and 
are usually so close to the surface that the pupae have no 
particular difficulty in getting out of the burrows when ready 
to change to adults. The length of the pupal life is not 
very great. The adults commence appearing in midsummer. 
There is one generation for each year. Treatment for the 
species has never been very satisfactory. There is no method 
known at once cheap and effective that can be easily applied. 
The most effective plan is that of cutting out the larvae 
from the burrows during the early autumn. A recent plan 
of mounding the trees and using a barrier applied close to 
the trunk with an adhesive that is pliable and non-injurious 
to bark, the collar flaring over the mound, is claimed to be 
effective. 

In the same family are the currant-, maple-, and syringa- 
borers. The food plant is rather restricted usually. 

Handmaid Moths. — Genus Datana, and species Datana 
ministra, have a quite peculiar habit as larvae. The moths 
are rather neutral-tinted forms and the larvae are quite 
conspicuous with a gregarious habit. They occur commonly 
on apple trees and other orchard trees, and where there is a 
nest of them the trees are badly stripped. They cluster in 
large masses and work in a company. At the periods of 
moulting they travel down the trunk to w^ithin a few feet 
of the ground and all moult at once and leave a large mass of 
moulted skins which adhere to the bark. After this moulting 
they travel back up the tree to the leafy portions and have 



FAMILY GEOMETRID^ 225 

another period of feeding. There are probably four or five 
different moults. At the last moult they are two and a 
half or three inches in length and about as thick as a pencil. 
They pupate in protected places and remain over winter 
in this stage, and the moths issue in the early summer and 
deposit eggs. They are very easil}^ controlled. When 
clustered during the moulting periods they may be easily 
gathered and killed. 

Family Geometridse. — The family Geometridoe includes 
the loopers. The larvae have a peculiar arrangement of legs, 
the abdominal legs being lost, except the last pair, and the 
movements being made with the thoracic legs. 




Fig. 175. — Paleacrita vernata: a, male moth; b, female moth; both 
natural size; c, joints of female antenna; d, joint of female abdomen; e, 
ovipositor — enlarged. (From Riley, Div. Ent., U. S. Dept. Ag.) 

Canker Worm. — The canker worm is one of the most 
important of these species economically. These are typical 
loopers and show some distinct specialization. There are 
two species closely related, and they are known as the fall 
and the spring canker worms. The spring form appears as 
an adult in early spring generally before the foliage is 
expanded on the trees, and the males and females are very 
different in their characters. The females are wingless and 
the males have . broad, thin wings. The females can gain 
access to the trees only by crawUng up the trunks, and the 
possibilities of distribution are limited by the distance which 
the females can crawl. They usually crawl up the trunks 
of the first tree they reach. The eggs are deposited on the 
twigs and hatch about the time the leaves are fairly opened. 
The larvffi are very destructive. In three or four weeks they 
15 



226 LEPIDOPTERA 

become fully developed, and drop to the ground by means 
of silken threads. They enter the ground for pupation and 
remain in the ground in the pupal stage through summer and 
fall and winter. 

The fall canker worm is almost the same so far as the life- 
cycle is concerned, except that the adults issue in fall. In 
this species the eggs remain over winter and hatch early in 
spring. Development is quite rapid and pupating is practi- 
cally the same as for the other species. The wingless con- 
dition, and the fact that they must crawl up the trees, gives 
one method of treatment. Anything that will prevent 
their going up the tree will protect the trees. Bands of tar 




Fig. 176. — Paleacrita rcrnata: a, larva — natural size; b, eggs — natural 
size and enlarged; c, side view of segment of larva; d, dorsal view of same 
—both enlarged. (From Riley, Div. Ent., U. S. Dept. Ag.) 



or oil on cotton will prevent their getting up the trunk of the 
trees. Small trees may be sprayed with arsenical solution 
as soon as they begin work in the spring. 

Noctuidse (owlet moths) include an immense number 
of common moths and a number of them very important 
species. The common name for the larval forms is cut worm. 
They differ from Geometers in adult characters and the wings 
are not so broad but fall close together on the back, sloping 
down the sides of the body. The hindwings are quite large 
but are not marked. The larvse are mostly without distinct 
coverings of hair, usually smooth and some of them subter- 
ranean in habit. 

One common and destructive species is the boll worm of 
the South, known in the North as the corn worm or tomato 



NOCTUIDM 



227 



worm. The larvse burrow into corn or tomatoes and do a 
great deal of damage. 

Another important species is the cotton worm {Alabama 
argillacea) which causes losses of millions of dollars in the 
cotton crop of the Southern States. Occasionally extensive 
flights of the moth bring swarms into the Northern States, 
and sometimes these adults attack fruits such as peaches, 
but it is not believed that the larvae grow on any Northern 
plant. 




Fig. 177. — Alabama argillacia: cotton moth on apple. 
Exp. Sta.) 



(Photo by Ohio 



Army Worm {Leucania uniyuncta). — The army worm is a 
widely distributed species in this country, only once in 
twenty or thirty years multiplying in such enormous num- 
bers as to attract general attention. When it does become 
abundant grass land is stripped entirely of the green leaves 
and the insects travel into adjacent fields to complete their 
growth. They travel in immense hordes and devour all 
vegetation as they go. Normally they are grass feeders and 
are found in pastures and meadows and only when they are 
unusually abundant do they migrate into other crops — wheat, 



228 



LEPIDOPTERA 



oats, corn, etc., when they may occasion considerable loss. 
In oat and wheat fields they may sim})ly cut off the heads. 
The life-cycle of the species is somewhat varied. It has been 
reported as passing the winter in various stages — egg, larvae 
and pupse. The moths appear in the summer and eggs are 
deposited in late summer or in autumn and probably a good 
many of the individuals pass the winter in the egg stage. 
Others become practically grown and then secrete themselves 




Fig. 178. — The army worm (Heliuphila unipuncta): a, full-grown army 
worm; 6, enlarged view of front of head; c, parent moth; c/, eggs in natural 
position on grass leaf; e, pupa; e, d, c, about natural size; a, enlarged 
about one-third. (Rearranged after Chittenden, Bull. 29, Div. Ent., and 
Comstock, Report of U. S. Ent. for 1879.) 



under the surface of the ground and hibernate. Others may 
reach pupal stage and still others may reach adult stage 
before winter. The great majority of the larval forms reach 
their maturity during May and June, and the greatest 
devastation usually occurs during the latter part of June 
and early July. Eggs are always laid in grass land and the 
larvae begin their growth in the grass. One brood is 
apparently the rule throughout the northern United States, 
and the difference in the stages observed during the year 



NOCTUIDM 229 

are due to irregularities and not to the appearance of more 
than one brood. The insect is rather hard to treat economi- 
cally because of its ordinary grass-feeding habit. When 
the enormous increase in numbers occurs, the time for check- 
ing them is really past. Something can be done for treat- 
ment. One way is to use trenching methods for capturing 
the larvse as they travel over grass land — trenches put 
across their line of travel and in this way large numbers 
may be captured and destroyed. It is also possible to spray 
the grass in the line of their march with arsenical solutions. 
These should not be used to pasture stock until the poison 
has had time to be washed out and no harm will be done. 
The trenches serve to prevent also the migration into wheat 
and corn or oat fields if adopted early enough. The species 
is parasitized quite extensively and when they become 
abundant the parasites also increase rapidly. Their increase 
is greater than that of the army worm. In this way there is 
a great check of the army worm. One of the most important 
of these parasites is the tachina fly which is closely related 
to the house fly, blow fly, etc. There are other parasites 
which are quite valuable also. 

Cut Worms. — The species known generally as cut worms 
are distributed through several genera and there are a 
great many species that occur in pastures and meadows, 
corn lands, and cotton, some of them are very abundant and 
destructive and some may be considered as annual pests. 
They usually live primarily upon grass and in the early 
spring migrate into gardens and cultivated ground, wdiere 
their destruction becomes very evident. One of the most 
important preventives is attention to grass land in autumn 
adjacent to or upon the area that is to be planted in garden 
or field crops. Tomato plants may be protected by tin 
cans, or metal strips bent into cylinders and placed around 
the plants and the cut worms may be killed by distributing 
bunches of poisoned clover among the plants to be protected. 
Some of the species are also attracted to light, and captures 
of the adults will serve some purpose in reducing the numbers. 
A feature of the work of cut worms not usually recognized 



230 LEPIDOPTERA 

is the regular loss in grass lands. In autumn and spring 
they feed on the grass plants and destroy a much larger 
amount of the growth of the grass than just what they eat 
themselves. They cut off the grass and it withers and is 
lost for either pasture or hay. The plant goes on growing 
and the injury is often unnoticed by the cultivator even 
where the cut worms occur by the thousands and the pasture 
lands must suffer a great deal of loss. 

The life history varies a little in different groups but most 
of the species that are troublesome occur in the adult stage 
in midsummer, depositing eggs which hatch in early autumn, 
and the larvae become practically grown and form little 
cells in the earth where they hibernate through the winter 
and issue in the spring and feed upon spring vegetation. 
Then they pupate in the ground in earthen cells and issue 
as adults in midsummer, any time from the first of June 
to the first of August. Different species may occur at differ- 
ent dates and in some cases it is important to determine 
the exact time of appearance for the particular species. 

Tussock Moths. — The tussock moths come in a different 
family and one species which is widely distributed is the 
white-marked tussock moth {Notolophiis leucostigma) . It 
is pretty troublesome in orchards and on shade trees, and 
occurs through the eastern United States and wxst to the 
plains region. The larvse drop oft' from shade trees on the 
sidewalks and on people who pass beneath. The larva is 
the most conspicuous form and much more beautiful than 
the adult. It is about two inches in length with rather bright 
yellow markings along the sides and with conspicuous tufts 
of yellowish hairs on the back and three quite conspicuous 
long black pencils of hairs, tw^o near the head and one on the 
tail end, several red spots and numerous whitish hairs. 
This larva when mature constructs a rather loose cocoon 
and pupates during midsummer and early autumn and in 
some cases the moths issue in a few days, in other cases not 
until the following spring. There are two broods in most 
cases, in others only one. In the case of two broods, those 
that appear late in the summer deposit eggs which hatch 



TUSSOCK MOTHS 



231 



and the larvae pupate and the moths appear late in the 
autumn. There is always an autumn deposition of eggs. 
The females are wingless and the males are winged with plu- 




FiG. 179. — White-marked tussock moth {Notolophus leuco stigma) . 
forming cocoon. (Photo by Ohio Exp. Sta.) 



larva 



mose antennse. They are gray in color. The females crawl 
out of the cocoon and do not leave it. After mating the eggs 
are deposited on the surface of the cocoon. They make a 



232 LEPIDOPTERA 

large white mass, the eggs being included in a frothy sub- 
stance which hardens and forms a varnish-hke coating 
which ghies tliem to tlie cocoon and protects them througli 
the winter. The eggs luitch in hite spring or early summer 
and the larvae grow, passing through several moults and 
reaching maturity in midsummer or perhaps a little late 
in summer. This is an insect that is single-brooded in a 
Northern locality but may easily become double-brooded in 
a Southern locality. This species is one for which the means 
of control may be readily seen. Egg masses are quite con- 
spicuous in the winter and it is an easy matter to gather 
these in the winter or late fall or early spring, and to destroy 
them by burning or crushing. The insect's eggs are fre- 
quently parasitized by minute hymenopterous parasites 
which lay eggs in the eggs of the tussock moths. These can 
be allowed to mature and provide another generation of 
parasites by putting the eggs where there is no vegetation. 
The parasites when matured escape and the larvse of the 
moths from unparasitized eggs wdll die. 

Gipsy Moth. — Closely related is the Gipsy moth (Porthet- 
ria dispar), an important species from Europe. It was 
introduced about forty-five years ago (1868 or 1869) and its 
importation was for experimental purposes and not with 
malicious intent. Eggs or possibly larvae may have been 
blown out of an open window and the species thus given its 
freedom. It did not attract much attention for several 
years. It became abundant near Maiden, Mass., and in the 
early nineties became quite destructive and attempts were 
made to exterminate it. In 1898, when its range had been 



LEGEND FOR PLATE. 

Gypsy moth {Porthetria dispar, Linn). (After Massachusetts State 
Board of Agriculture.) 
1, female with wings expanded; 2, female in resting position; 3, male 
with wings expanded; J^, male in resting position; 5, pupa; 6, dorsal view 
of one of the larger caterpillars, presumably a female; 7, dorsal view of one 
of the smaller full-grown caterpillars, presumably a male; 8, egg cluster 
on a piece of bark; 9, a few eggs greatly enlarged; 10, one egg still more 
enlarged. 



/ * 



n 



.^ 



yt 



A ' > 

.i, ' 





JO 



'^ 





GIPSY AND BROWN-TAILED MOTHS 233 

much restricted, the State discontinued its efforts, and in a 
few years it had spread over a large area and its extermina- 
tion was deemed impossible. A few years later State and 
National efforts for control were inaugurated and have been 
pushed vigorously in several different ways. The species has 
caused great losses, and both State and National govern- 
ments have spent great sums in attempting to keep it from 
spreading and increasing. 

The life history of the species is an important factor in 
control. The moths appear in midsummer and autumn and 
the males and females differ in appearance but both have 
wings, though those of the female are weak and their flight 
is limited. Distribution of the species by the flight of the 
females seems to be almost nothing, and the spread of the 
species is mainly by the distribution of caterpillars. The 
eggs are deposited in late summer and the egg masses sur- 
vive the winter attached to trees, bark, etc. They hatch 
in spring or early summer and the larvae make their growth 
during the early summer months. They may be so numerous 
as to almost completely strip the foliage of plants. At such 
times the caterpillars make every effort to scatter, attach- 
ing themselves to vehicles, etc. There are several parasites 
for the species, but none which are distinctly effective in 
this country in keeping the species down. Different methods 
adopted by the Massachusetts Commission are extremely 
interesting. A volume has been published on the Gipsy 
moth. Spraying, burning, scraping of trunks of trees, etc., 
have all been used. In one instance every inch of an 
immense elm tree was gone over. Extended efforts have been 
made to introduce parasites and predaceous enemies to aid 
in control of the species. 

Brown-tailed Moth. — ^Another species of rather recent 
introduction is the brown-tailed moth which was first 
observed in Massachusetts in the vicinity of Boston about 
the year 1890 or 1891. This is a native of central Europe 
and is particularly common in France and Germany where 
it is recognized as a destructive species. The female flies 
readily, and thus it has spread more rapidly than the Gipsy 



234 LEPIDOPTERA 

moth, and now occurs tliroughoiit tlie eastern part of Mas- 
sacluisetts, New Ilampsliire, and eastward into New Bruns- 
wick and Nova Scotia, south and west into Connecticut. 
It is quite certain to spread by degrees througliout a large 
part of the entire forested portion of North America. The 
adults are white with the hinder portion of the abdomen 
brown. The eggs are laid on trees in small clusters and have 
a brown appearance. The larvse hatch in early autumn and 
the caterpillars become about half-grown before winter and 
then spinning up in clusters, form a nest of leaves and web 
in which they secrete themselves for the winter. In spring 
with the opening of foliage they wander from these nests, 
attacking the foliage and causing serious injury, completely 
stripping the trees, so that they may be killed especially if 
the attack is repeated for two or three seasons. The larv^se 
complete their growth by early summer, pupate, and pro- 
duce moths in late summer, thus completing the annual cycle. 
The larvse feed exposed on the foliage and may be killed by the 
arsenical sprays when occurring on orchard or shade trees, 
where it is possible to reach them with the spraying machin- 
ery. An evident means of control is to destroy the over- 
wintering insects during fall, winter or early spring when 
they should be conspicuous on leafless trees. They are 
easily shipped from place to place on twigs or small trees 
and should be excluded by inspection of shrubs, trees, or 
cuttings that are imported. 

While not at present established as pests outside of the 
New England States, these insects deserve to be watched 
and particular pains taken to prevent their dispersal. Such 
watchfulness may serve to greatly retard the distribution 
and postpone the time when they may be destructive in any 
particular region. 

Web-worm Moths. — The web-worm moths are little, white, 
with femur of front legs of yellow or orange tint, and the 
legs and feet with little touches of black. These moths are 
plentiful during the summer — about the last of June. They 
deposit eggs in masses on the under surface of the leaf. 
When the young hatch they usually first attack the leaves 



TENT CATERPILLAR 



235 



on which the eggs were deposited, enclosing it in a web and 
the whole colony begins to feed on a single leaf adjacent 
to it. After the first moult they pass to other leaves and 
include large numbers of leaves and sometimes the whole 
tree. The entire colony feeds within the silken web. None 
of them go away to scatter over the tree. There are several 
moults, about five. They pupate a little later in the season 
and the adults issue in the following spring. Two broods 
are known in some localities. It is a great pest in orchards 








^ Fig. 180. — The fall web worm {Hyphantria cuneo) : a, dark larva from 
side; &, light larva from above; c, dark larva from above; rf, pupa, ventral 
view; e, pupa from side; /. adult. All slightly enlarged. (After Riley.) 

and occurs on more than one hundred kinds of plants. The 
web worms are so conspicuous that there is little excuse for 
neglecting them and clipping off the newly formed web 
with the end of the twig infested, or crushing or burning the 
colony is so simple a matter that no one should permit 
them to multiply. 

Tent Caterpillar {Clisiocmnpa americana). — This is some- 
times called the American tent caterpillar. The Western form 
is called the Western tent caterpillar. They are more com- 



236 



LEPIDOPTERA 



mon in orchards than in forests. The}' differ from the fall 
web worm both in life history and in the character of the 
tent or web and in the habits of the larvae. The adults are 
heavv-bodied and hair\', with lon*,^ slender scales. They 



, ^^.. 


^■xs 






ik 


»h.. 










^ 




■^ 


^""^^^^P^ 




^mT 


^^^^K 


:;^g 


^ 


1 


0' 


PC ■ 





Fig. 181.— Web of fall wob worm enclosing colony. 
Exp. Sta.) 



(Photo by Ohio 



TENT CATERPILLAR 



237 



appear rather early in the autumn, depositing masses of 
eggs in circles around the twigs, usually completely encircling 
the twig. The eggs are glued together very firmly with a 
varnish-like substance that covers and protects them for 
the winter season. The largest part of the time is spent in 
the egg stage, that is, through autumn and winter and 




Fig. 182.— Webs of fall web worm (Hyphantria cuned) on defoliated 
walnut tree. (Photo by author.) 

through early spring. The eggs hatch quite early, about 
the time the foliage expands or a little in advance of the 
foliage, and the larvse construct a nest generally in a crotch 
of a rather fair-sized branch— perhaps an inch and a half 
in diameter. The web fits into the crotch and extends out 
beyond it. The web is not much increased after first formed. 
The larvge scatter when feeding on the leaves and retire to 



238 



LEPIDOPTEHA 



the tent for ])r()tcc*ti()n wIkmi not feeding. In this tliey differ 
from the fall web worm. They have fairly distinct times of 
feeding and of resting, the feeding l)eing })erhai)s more com- 
monly done in the early, cooler part of the day, perhaps more 
or less at night, and protection in the web being sought in 
the middle of the day or tlie hottest ])ortion. They get their 
growth pretty rapidly, requiring only a few^ weeks in early 
spring for their development, and then they scatter mainly 







^g 



^ d 



Fig. 183. — Stages of the apple-tree tent caterpillar: a, egg mass; b, 
larva; c, pupa'; d, cocoon; 9, female moth; ^f, male moth. About 
natural size. (After Quaintance, Div. Ent., U. S. Dept. Ag.) 



from the nest and construct cocoons in all sorts of protected 
places, under bark, under boards, on fence posts, under 
ground, etc. The cocoon is rather irregular, not very com- 
pact and within the cocoon they change to pupae. This 
pupation or change to the pupal stage takes place soon after 
the cocoon is formed. They remain in the pupal stage only 
about three weeks and then issue as moths, coming out in 
the summer. They do a great deal of damage which is rather 
more pronounced because of the early attack on the foliage 




M^''''4;^ 







Fig. 184. — Apple-tree caterpillars (Malacosoma americana) and "nest;" 
egg mass or belt on small twig at left. "Nest" considerably reduced; 
caterpillars one-half natural size. (After Quaintance, Div. Ent., U. S. 
Dept. Ag.) 

(239) 



240 LEPIDOPTERA 

before it is fully expanded. A single nest may ser\e to 
defoliate an entire tree of ordinary size. The method of 
destroying them will be a little different from that of the 
fall web worm on account of the habit of scattering over the 
tree. To kill the entire colony it is necessary to take the 
time they are all in the nest, when they can be destroyed 
as easily as the fall web worm. The best way is to destroy 
the egg masses. The egg masses are conspicuous enough to 
be readily seen and by destroying them the injury for the 
following season can be prevented. They are readily con- 
trolled in this manner. When foliage is on the tree the 
egg masses are not so readily seen. A little attention for 
a year or two will practically rid an orchard of these pests. 
They are heavy-bodied and although winged, do not travel 
far. The moths are a dark gray or slightly rusty brown 
and are much like a number of other moths. Two light bands 
extend across the wing a little obliquely to the axis of the 
wing. These are bordered by a slightly darker stripe. 

The forest tent caterpillar is very similar in the appearance 
of the larvae and in the building of the tent but difl'er in the 
egg masses. The eggs stand straight out; and this species 
is not so important as the tent caterpillar. 

The Cecropia moth, Luna and American silk worm are also 
quite prominent, but are not as important economically 
as the preceding species. All are silk-making forms, but 
their silk production does not compare with that of the 
Chinese worm. The silk worm is the most important insect 
considered from a stand-point of producing an important 
product — the honey bee is the only other of great impor- 
tance. The silk industry will perhaps come into greater 
prominence in this country if labor is cheaper or there is a 
larger class of unemployed, as it requires a great deal of 
attention but no great skill of labor. Too much time and 
trouble are necessary to rear silk worms profitably in a greater 
part of the United States. In France, Italy, China, and 
Japan it is a very large industry. 

This finishes what are known as the moths proper — the 
Lepidoptera which have antennie without an}' knob at the 
end and which are almost all night-flying. 



PAPILIONID/E 



241 



The next group are day-flying, butterflies, etc., and have 
a different form of antennae. The skippers are somewhat 
intermediate. Their antennae are slender and run out. 
sometimes into a hook, or end in a thread-like structure. 
The butterflies have a thickening at the tip of the antennae. 
Butterflies are strictly diurnal and are contained within 
four or five distinct families. Hesperidae are intermediate 
not only in these antennae but also in the wings. In the 




Fig. 185. — Cecropia moth, larva; natural size. (Photo. Ohio Exp. Sta.) 

butterflies the wings are folded up vertically over the back. 
In Hesperidae they are about half and half. Some fly at 
twilight — the yucca-borer — others in the daytime. 

Superfainily Painlionidoe includes the swallow-tailed 
family. There is a tail-like appendage on the hindwings, 
which varies considerably in different species. The larvae 
are most of them characterized by the presence of peculiar 
fleshy organs which are projected from the segment behind 
16 



242 LEPIDOFTERA 

the head. Tliis fleshy organ is thrown out when they are 
irritated. It gives oft* a very pecuHar odor characterized by 
some as Uke the flavor of ripe peaches. This is presumably a 
protective device. The caterpillars are many of them 
banded distinctly and others have rather neutral colors and 
eye-like spots on the body. A large black form with yellow 
stripes on the wings is one of the most common here. In the 
South it feeds on the orange and is known as the orange dog. 
In Northern localities it feeds on the prickly ash and the 
pawpaw. The caterpillar of this species, Papilio cresphontes, 
has much the appearance of the excrement of birds. In most 
of the Northern States the species is rather rare, but in the 
South is quite abundant. 

Pieris rapse, in the family Pieridoe, is the common cabbage 
worm or cabbage butterfly. This species was introduced 
from Europe into America some forty or fifty years ago, 
probably in the vicinity of Quebec, and has spread over all 
the eastern United States and practically over all the country. 
Its life-cycle is pretty definite and the broods are pretty well 
marked, there being two broods each year. Starting with 
the adults that appear in spring or early summer, eggs are 
laid on cabbage or other cruciferous plants and after hatching 
from the eggs, the larvae develop by midsummer and adults 
of this generation lay eggs that hatch the latter part of 
July or in August and develop during August and September 
or October. This brood feeds particularly on the cabbage 
heads which may be tunneled through quite well into the 
interior or at least well through the outer leaves, damaging 
them for use. The larvae are green in color and well protected 
either outside or inside of the leaves. The larvae develop 
through autumn and mature by cold weather by the time 
that the plants give out and then change to pupa?, the 
chrysalids being formed in fence corners, sides of buildings, 
and other protected places. Sometimes they get into build- 
ings and sometimes simply under rubbish. They are likely 
to travel considerable distances from the plants on which 
they have fed. They pass the winter in this stage and the 
butterflies issue in spring and deposit eggs for the first brood 



ALFALFA CATERPILLAR 243 

of larvae upon any of the crucifers available. Early cab- 
bages may be attacked, the larvse feeding simply on the 
leaves. Eggs are commonly deposited on wild mustard, etc., 
and the larvte develop on these plants. The pupal stage for 
the first brood is quite short, about two weeks to twelve 
days. There is enough variation in the time of appearance, 
so that the butterflies may be present for three or four weeks 
in both spring and summer, and so they are to be found 
pretty well through the summer months up to the middle of 
August or the first of September. The great bulk of them 
come at about the time vegetation is opening up and again 
about the jSrst of August. The species is not very easily 
controlled. It lives on a variety of food plants and is two- 
brooded and this helps in sustaining it. If the first brood 
could be destroyed it might be controlled, but it is hard to 
do this. Trap crops may be planted, as mustard, etc., 
and then the entire crop destroyed after the eggs are deposited 
on it. Butterflies can be captured while depositing eggs, a 
cheaper method than applying insecticide. Remedies can 
be applied to the cabbages, especially before they have 
headed without any danger to the eating of the cabbages 
after they have grown. It should be done with precaution, 
especially after the cabbages have reached some size. If the 
solution is the right strength, there is practically no danger, 
as twenty-eight cabbages would have to be eaten at one meal 
to poison a person. The best way is to apply poison before 
the cabbages are headed out. If the treatment is pretty 
thorough for the first brood and the early part of the second, 
the effect will be pretty successful. Gathering of the pupse 
is possible, but is not practicable on a large scale. It is 
better not to destroy these, but to pass them into a receptacle 
with a wire screen so that the parasites may escape while 
the butterflies do not. The parasites are sometimes abun- 
dant and greatly reduce the numbers and in some seasons 
render the use of remedies unnecessary. 

Alfalfa Caterpillar {Eurymus eurytheme). — The alfalfa 
caterpillar is a common species over most of the United 
States and has attracted attention as a serious pest in the 



244 



LEPIDOPTERA 



alfalfa-growing districts of the West and Southwest. In the 
Eastern States it is less abundant but still plentiful enough, 




Fig. 186. — The alfalfa caterpillar (Eurymus eurytheme) : female in the 
adult or butterfly stage. One-half enlarged. (After Wildermuth, Bur. 
Ent., U. S. Dept. Ag., Fig. 2.) 




Fig. 187. — The alfalfa caterpillar {Eurymus eurytheme) : male in the adult 
or butterfly stage. One-half enlarged. (After Wildermuth, Bur. Ent., U. 
S. Dept. Ag., Fig. 3.) 



SO that it must have an effect on the clover crop on which 
the larva feeds. 



MONARCH BUTTERFLY 



245 



In the Eastern Mississippi Valley and Atlantic Coast 
States it is perhaps less common than the related sulphur 
butterfly, Colias philodice, which is so plentiful as adults 
that it is fair to assume an abundant progeny feeding in 
clover fields. 




W 



wi JR W Hk^p^bII 



Fig. 188 



Fig. 189 

Fig. 188, — The alfalfa caterpillar: egg — greatly enlarged. (After Wilder- 
muth redrawn from Soudder, Bur. Ent., U. S. Dept. Ag., Fig. 4.) 

Fig. 189. — The alfalfa caterpillar (Ewymus eury theme) : larva or cater- 
pillar stage — about twice natural size. (After Wildermuth, Bur. Ent., U. 
S. Dept. Ag., Fig. 1.) 




Fig. 190. — The alfalfa caterpillar {Eurymus eurytheme) : pupa or chrys- 
alis stage — twice natural size. (After Wildermuth, Bur. Ent., U. S. Dept. 
Ag., Fig. 5.) 



Monarch Butterfly {Anosia plexippus). — The monarch but- 
terfly (family Danaidce) is interesting in two or three ways, 
though not of any special importance economically. It is 
one of the largest butterflies outside of the Papilios, and it 



246 LEPIDOPTERA 

is pretty readily rec()f]jni/e(l })y tlie dark re(ldisli-})r()wii color 
with black bands and stri})ings and the border including a 
number of white sj)ots. It deposits eggs on milkweed as its 
host plant. These eggs hatch very shortly and the larvtTe 
develop during the latter part of the summer and i)upate 
and become adults in autumn, and it is quite common in 
October to see immense swarms of these butterflies. They 
gather along hedge rows and on trees, sometimes appearing 
by millions. Late in the afternoon they will cluster on the 
branches in immense numbers. At the time of their gather- 
ing in immense numbers they seem to have a general south- 
erly movement and they are known to migrate at least to 
some extent during the autumn, though the migrations 
probably do not cover as long distances as that of birds — 
not over 200 to 500 miles. They appear in great abundance 
in the South in the winter. It is not possible to follow indi- 
viduals for very great distances, but evidently they hibernate 
in the adult stage in the South and it is pretty generally 
believed that the hibernating individuals in Northern locali- 
ties are likely to perish. Individuals that start the first 
generation must have travelled from the South. The spring 
individuals are frayed and give evidence of having travelled 
some distance. The spring-appearing individuals deposit 
eggs and from these the generation of caterpillars comes 
that mature during midsummer. The adults appear in the 
latitude of New York about the middle or last of July. 
There are two distinct generations for each year. The cater- 
pillar is quite prominently banded and has some striking 
thread-like appendages. It reaches the length of one and a 
half or two inches and is nearly as thick as a pencil. It is 
found particularly on the milkweed. Their pupation occurs 
by attachment to the leaves of the milkweed or plants or 
objects convenient or adjacent to the host plant. The pupa 
cases are attached by a sort of spur or hook at the posterior 
end of the body caught into a little web that has been spun 
on the leaf. The larvse locate on a suitable object and spin 
a little web and then the larva contracts and the larval skin 
splits along the back and this larval skin is held by the pos- 



NYMPHALIDM 247 

terior segment in such way that it can twist the pupa case 
around and catch the hook of the pupa case into the web. 
The pupa case lasts only a week or ten days and then gives 
rise to the adult form. It is mimicked by a species which has 
an additional black band on the hindwing and there are 
differences in the legs. This, the viceroy (Basilarchia 
archippus) has evidently gained protection by taking on 
the appearance of the monarch. 

One other species in the family Nymphalidw that should 
be noticed is the common mourning cloak vanessa {Euvan- 
ess a antiopa) which is interesting because of its very wide 
distribution and its very great hardihood. It is said to occur 
over practically all of the northern hemisphere from 30° to 
the Arctic Circle. It occurs here in the winter time, hiber- 
nating as an adult and has been found secreted in hollow 
logs, bridges, and in almost any sheltered place, and if 
taken indoors will revive and feed on sweetened water 
quite readily. They begin to fly quite early in the spring. 
It is double-brooded — the eggs deposited in early spring 
produce larvae which mature in midsummer. They breed 
on willow particularly and the larvse are dark-colored and 
rather conspicuous. They also infest poplar, elm, and 
dogwood, but willow seems to be the favorite. The chrysalis 
is attached to the twigs of these plants and the adults 
appear in midsummer. These adults deposit eggs and a 
second generation appears in autumn which hibernates and 
carries the species over winter. In some places they have 
an economic importance, but ordinarily they are not a 
serious pest, and the butterfly is such a handsome species 
that it may be counted as deserving immunity. 



CHAPTiP:R IX. 
ORDER DIPTERA. 

Tins is a very large and important order and includes a 
number of important economic species such as the house 
fly and the mosquito. They are separated from all other 
insects by the wing structure, the front wings only being 
fully developed as means of flight and the second wings 
being modified into knob-like structures which seem to. have 
some use in sustaining the insect in a certain position. 
They vibrate but cannot serve any distinct function as a 
means of flight. They are modified wings. This is a case of 
specialization, reduction in size. This is coordinated with 
the centralization of the nervous system. There is distinct 
metamorphosis whose stages are usually sharply marked. 
The larvae are usually called maggots, those of the mosquitoes 
"wrigglers." The larvse occur in all manner of situations. 
Some are aquatic, some terrestrial, some subterranean, etc. 
The group is separated mainly by larval characters — one 
group including mosquitoes and gnats, another the more 
specialized flies. The larva contracts and the skin hardens 
and forms a pupal case whose end splits off like a cap. 

The Orthorapha, mosquitoes and gnats, are the less 
specialized or the more primitive group. 

Of the groups in the first series the mosquitoes (CulicidcB) 
are the most in evidence, if not the most important, and 
are receiving more attention lately because of their asso- 
ciation with the transmission of various diseases. The 
mosquito is not a single species. There are a great many 
different species and they differ a great deal in life history 
and habits and in their relation to disease. The most general 
statement to be made regarding their cycle is that the eggs 
( 248 ) 



MOSQUITOES 



249 



are deposited on the surface of the water and perhaps in 
some species in mud or damp earth. The larvse are essentially 




Fig. 191. — Anopheles maculipennis: male. Fig. 192. — Anopheles maculi- 

Carrier of malaria. (Harrington.) pennis: female. Carrier of 

malaria. (Harrington.) 




Fig. 193. — Anopheles punctipennis: male. 
Howard.) 



Carrier of malaria. (After 



250 



ORDER DIPTERA 



aquatic and air-l)roathin<]j, witli tlie trachea opening at the 
end of tlie abdomen. TJie \)\\\)iv are also acjuatic but keep 
near the surface and spiracles o])en near the head. The pupa 
case splits on the dorsal side and the mosquito rests on the 




Fig. 194. — Anopheles^ punctipennis: female. (From Howard, 
Div. Ent., U. S. Dept. Ag.) 



surface of the water until its wings are dried enough for flight. 
One species has been observed whose eggs may remain over 
winter in mud, and hatching and development depends upon 
the presence of water. Mosquitoes breed in minute quanti- 



MOSQUITOES 



251 



ties of water if they have it for a few days, and especially 
those that are more common about towns depend on small 
pools, tanks, and rain barrels rather than larger bodies of 
water. More breed in small pools than large, because there 
are usually no fishes in the small pools. They fly for a few 
rods but for no extreme distance — one-half mile or a mile. 



<^^' 




Fig. 195. — Culex tceniorhynchus: female showing the short palpi which 
distinguish Culex from Anopheles; toothed front tarsal claw at right — 
enlarged. (From Howard, Div. Ent., U. S. Dept. Ag.) 

They may be transported, but most annoyance comes from 
those bred close at hand. The connection between mosqui- 
toes and malaria has been fully established. The parasite 
seems to be dependent upon two distinct hosts. Unless 
there is a case of malaria in the near vicinity they cannot 
communicate it to another. The relation of mosquitoes to 
yellow fever has also been w^orked out very carefully. One 



252 



ORDER DIPTERA 




Fig. 196. — Resting positions of Culex (at left) and Anopheles (at right) — 
enlarged. (Redrawn from a rough sketch published in the British Medical 
Journal.) (From Howard, Div. Ent., U. S. Dept. Ag.) 




Fig. 197. — Yellow-fever mosquito (Stegomijia fasciata) : A, male; B, 
female. (After Howard.) 



GALL GNATS 253 

striking thing is the discovery of the immense number of 
species of mosquitoes. There have been many new species 
discovered in the last few years. 

Gnats {Chironomidce) . — Gnats are related to mosquitoes 
and are interesting partly because of their close resemblance 
to mosquitoes and partly because they occasionally multiply 
so as to cause annoying contamination of reservoirs or 
obstruction in water tanks. The antennae are plumose as 
in the mosquitoes but the mouth parts are different. The 
larvse are more distinctly aquatic than the mosquito larvae — 
can survive down in the water without coming to the sur- 
face for air. Some live in mud — slender red, worm-like crea- 
tures. One species is quite plentiful in the Northern States 
especially near lakes and sometimes as abundant as the May 
flies. 

Gall Gnats. — The next group is the one including the gall 
gnats. It is a very important family with two or three very 
important species. The most conspicuous of the galls 
produced by these is the cone g^ll produced on willow trees — 
the pine cone willow galls. These are the result of the work 
of the larvae of the gall gnats. They are made up of a series 
of leaves which overlap in the form of a pine cone. These 
correspond with the leaves that would have come out along 
the twig had it grown out normally. The leaves are devel- 
oped close together and the larvae of the gall gnat is found 
in a little cell in the centre of the gall. It issues in the spring 
and deposits its eggs in the willow buds before the twigs 
have started to grow, and the larvae hatch and form the galls 
b}^ feeding. There are a good many things in these galls 
besides these larvae. Other insects find them a convenient 
shelter, and other insects deposit eggs there. The tree 
crickets are an example of this. These may be a little mis- 
leading but they have nothing to do with the formation of 
the gall. The pine cone gall is most conspicuous. There 
is another species which simply produces an aborted growth 
that looks like Brussels sprouts. 

The other species in this family to be mentioned are the 
clover and wheat midges and the Hessian fly. 



254 



ORDER DIRTERA 



Clover-flower Midge {T)asyncura Icguviinicola). — The clover- 
flower iiiidn'c^ lives within the heads of clover and feeds upon 
the clover bloom and seed. Its life-cycle is adapted to the 




Fig. 198. — The clover-flower midge {Daayncura legtuninicola) : n, enlarged 
dorsal view of male with scales denuded; b, head; c, genitalia; d, antennal 
joints, more highly magnified, to show structure; e, tarsal claw; /, /, forms 
of scales. (From Riley, Div. Ent., U. S. Dept. Ag.) 



blooming of the clover, so that the larviie appear at the })roper 
time for feeding upon the clover seed. There are two fairly 
distinct broods each season, the first brood of larvae develop 



HESSIAN FLY 255 

in early summer and mature in midsummer, the larvse issuing 
from the clover heads and pupating in the ground and the 
second brood appearing later in the summer and depositing 
eggs which produce the second generation of larvae which 
develop in the later blooming clover. These hit the crop 
of clover grown for seed. They mature with the late autumn 
and either maggots or the mature puparia would be found 
during the winter time and the larvae particularly which are 
caught before they have completed their growth may be 
included in clover seed. The fully developed larvae pass 
into the pupa stage at the surface of the ground. It is 
doubtful if the midge can be transported from one place to 
another by means of the clover seed. Just how it is intro- 
duced into remote districts is uncertain. Its means of loco- 
motion is by its own flight. It is pretty generally dispersed 
throughout the portion of the country where clover is now 
grown. The means of treatment would lie more in the 
direction of cutting the clover at the time to cut short the 
growth of the larvae — a little earlier cutting of the clover, 
catching the larvae before they have issued from the clover 
heads. 

Hessian Fly (Mayetiola destructor), — The Hessian fly is 
the most destructive of the family. It is an introduced 
species and was first described from materials in this country 
in 1820. It probably originated where wheat did. It was 
never described scientifically until by Say. It had been 
known as a destructive insect earlier than 1820 and the 
name was given to it about the time of the Revolution, when 
the Hessian soldiers were in this country, either because the 
insect was thought to have been introduced by them or as 
an obnoxious name. The name was adopted over the entire 
English-speaking world. The evidence that it is an old- 
world species is from its food plants and that it spreads 
from one centre. There are a number of other evidences. 
Its natural food plants seem to be limited to wheat, rye, and 
barley, though there is a question as to barley. It was 
proved by a Frenchman that it does not occur on oats. At 
one time it was thought to breed in various grasses, but later 



250 



ORDER DIRT ERA 



studies show that this was not the true Hessian fly. If any 
attempts are made to control it by rotation of crops its 
restriction of food plants should be well known. Its life- 
qycle is quite similar to that of the clover-flower midge and 
it has become very distinctly adapted to the crop it infests. 
Any great change in ordinary methods of raising wheat 
would likely prove destructive to the insect. The winter is 




Fig. 199. — The Hessian fly (Mayetiola destructor) : adult female — much 
enlarged. (After Webster, Div. Ent., U. S. Dept. Ag.) 



passed in the flaxseed stage — the puparium stage. The 
larval skin shrinks and forms a tough, dark brown covering 
about the size and shape of a flaxseed. Within this there 
is formed a real pupa that has the outline and features of the 
adult insect. There is a distinct metamorphosis. These 
hibernating puparia give rise in early spring to adult midges 
that deposit eggs on the stems and leaves of wheat plants — - 



HESSIAN FLY 



257 



winter wheat. In spring wheat regions the flies appear 
at about the time of the coming up of the wheat and deposit 
eggs on it. There is not necessarily much difference in the 
time and method of deposition except that those on winter 
wheat are apt to be a httle higher on the stems and farther 
from the ground. These burrow into the stem in such a 
way as to cause weakening of the stalk, which is apt to bend 




Fig. 200.— The Hessian fly: 
Marlatt, Div. 



adult male — much enlarged. (After 
Ent., U. S. Dept. Ag.) 



and break as it approaches maturity and falls to the ground, 
so that it cannot be harvested. Sometimes only 1 or 2 per 
cent, of the field will be infested and in other fields one-third 
or one-half of the crop will be lost. As the wheat matures 
the larvae mature and change to the flaxseed stage and 
remain protected between the sheath and the stem of the 
plants down near the ground. Sometimes they are 
17 



high 



258 



ORDER DIRTERA 



enough to be cut off aud carried witli the straw when the 
wheat is luirvested, })ut more commonly are left in the 



i 




Fig. 201. — Egg of Hessian fly — greatly en- 
larged; section of leaf of wheat, at right, 
showing eggs as usually deposited, less 
enlarged. (After Webster, Div. Ent., U. S. 
Dept. Ag.) 



Fig. 202.— The Hess- 
ian fly: larva before "flax- 
seed" is formed — much 
enlarged. (Webster, Div. 
Ent., U. S. Dept. Ag.) 





Fig. 203. — The Hessian fly: larva 
taken from "flaxseed," much enlarged 
with "breast-bone" still more enlarged 
at right. (After Webster, Div. Ent., 
U. S. Dept. Ag.) 



Fig. 204. — The Hessian 
fly: puparium or "flax- 
seed," much enlarged. 
(After Webster, Div. 
Ent., U. S. Dept. Ag.) 



stubble. They survive the midsummer in this condition and 
are apparently dependent more or less on conditions of 



HESSIAN FLY 



259 



temperature and moisture. They come out in the fall and 
are ready to deposit eggs on wheat plants accessible in the 




Fig. 205. — The Hessian fly: pupa taken from "flaxseed," greatly 
enlarged. (After Marlatt, Div. Ent., U. S. Dept. Ag.) 




Fig. 206. — Injured plants and flaxseeds. (Photo by Ohio Exp. Sta.) 



260 ORDER DIPTERA 

autumn. The eggs deposited in tlie autumn give rise to larvse 
which develop and ])ass into the flaxseed stage to hiberuate. 
If they are accelerated in their development and are provided 
with food material — volunteer wheat — there may be one or 
more extra broods in the summer. As high as five or six 
extra broods were observed by Marchal. Tliere are ordi- 
narily two broods adjusted to the occurrence of young wheat 
plants. One important thing is the distribution of the 
species by means of the shipping of infested straw. This 
must be the main or only means by which the species is 
taken from one country to another. It has been introduced 
into most wheat-growing countries of the world. The 
natural distribution of the species is limited to about 20 
miles a year. Flight aided by the wind might carry it some 
little distance. For local measures attention to the stubble 
is one of the most important things. If it is thick and dry 
enough to burn over during midsummer, it can be destroyed 
in this manner. Plowing under very deeply is another 
method but must be done early enough to bury the stubble 
before the flies have issued. The most generally practised 
method, and most highly recommended, is to adjust the time 
of planting so as to avoid the period of egg deposition. If 
the time of planting wheat can be deferred for a week or two 
after the appearance of the flies, it will escape. Flies will 
not deposit eggs on the bare plowed field. If the wheat comes 
up after the flies have issued and passed the egg-laying period, 
it escapes attack. For the Central States the time of appear- 
ance has been pretty definitely determined, and it has been 
shown at what time wheat can be planted with the greatest 
security. For the latitude of Columbus, Ohio, it is about 
the first of October. It is possible to plant trap crops so as 
to catch the flies as they appear and the whole crop can be 
plowed under after the eggs are deposited on it. This is not 
particularly popular. If planting is done with reference 
to temperature and to different seasons, results will be better. 
Hot, dry weather seems to prevent the issuing of the flies. 
Family Simuliidse.— The family SivudiidcB includes the 
black flies and buffalo gnats. These constitute extremely 



FAMILY SIMULIID^ 261 

injurious pests and occasion many losses to agriculturists, 
so that they deserve a paragraph at this point, although for 
most of their existence they have very little in common with 
farm life. They have had an added interest in recent years 
on account of the effort to prove them the carrier of the 
disease known as pellagra, but proof of such a connection 
is still wanting. The adults are short, small, thick-bodied 
insects; the thorax especially heavy, and the humped appear- 
ance of the whole body has given rise to the name buffalo 
gnats. They are all small species, scarcely any of them a 
quarter of an inch in length. The larvae are distinctly aquatic, 
usually living in swiftly running water. They are so fully 
adapted for aquatic life that they attach themselves by 
silken threads to submerged objects and depend for their 
food upon minute organisms floating or swimming in the 
water. The pupal stage is also passed under water, a thin 
cocoon being spun upon the under side of the leaf or other 
submerged object. When the adults emerge from these they 
rise rapidly to the surface of the water, the wings expanding 
promptly, and they are ready for flight almost instantly. 
At times they occur in enormous swarms and the females 
are very blood-thirsty, attacking all kinds of warm-blooded 
animals, sometimes with very disastrous results. In the 
Northeastern States and in parts of Canada, especially in 
Labrador, there is a species known as the black fly. They 
occur at times in such abundance as to make it practically 
impossible to remain out of doors, and domestic animals will 
seek any possible shelter in order to avoid the attacks of the 
insect. In the Southern Mississippi Valley there are two 
common species which have been studied in detail. One of 
these, the turkey gnat, is said to make its attacks very gen- 
erally upon poultry, although it is not limited to these animals. 

The other species which is credited with the greatest 
amount of loss in the Mississippi Valley region may be 
considered somewhat in detail and as a representative for 
the family. 

Southern Buffalo Gnat (Sivmlumi pecuanim, Riley). — The 
investigations of 1885-86-87, which have been reported very 



262 



ORDER DIPTERA 



fully in the Department j)ul)lic'ati()ns, and from which the 
statements here made are mostly compiled, liave shown 
that the extent of territory invaded by these insects is much 
greater than formerly su])])osed. It may be stated to com- 
prise, in the worst years, the whole of the Mississippi Valley 
from the mouth of the Red River, in Louisiana, to St. Louis, 
Mo. All the adjacent land to the many rivers and that 
empty from the east and the west into the Mississi])pi River 





Fig. 207. — Simidium pecuarum: larva — enlarged. (From Annual 
Report of Department of Agriculture, 1886.) 



is invaded by swarms. They are driven about by the wind 
and reach points far aw^ay from their breeding places. 

The extent of the losses due to this species has already 
been stated, though it is, of course, impossible to separate the 
losses due to this species from those caused by the turkey 
gnat. Li a general way the latter may be said to be more 
destructive to poultry, while the attacks of this species are 
more particularly directed against the larger domestic 
animals. 



FAMILY SIMULIIDM 



263 



The larva is not differeint in general appearance from that 
of other species. The annexed cut (Fig. 207) shows it con- 
siderably enlarged and will make a detailed description 
unnecessary. It is translucent when living; the body in 



\7l\ 




: i 



Fig. 208. — Sinmlium pecuarum: head of larva: a, beneath; b, side; 
c, above — greatly enlarged. (From Annual Report of Department of Agri- 
culture. 1886.) 





Fig. 209. — Simulium pecua- 
rum: pupa — enlarged. (From 
Riley.) 



Fig. 210. — Simulium pecua- 
rum: female, side view — en- 
larged. (U. S. Dept. Ag.) 



some individuals is without markings, while in most it is 
distinctly marked with dark cross bands on the back in the 
middle of the joints, while at each side is a white space; 
the under side is more or less irregularly spotted with brown. 



264 



ORDER DIPTERA 



The head is yellowish-brown, nearly square, horny, and 
marked as in the figure (Fig. 208). 

The tip of the abdomen is crowned witli rows of hooks, 
and on the upper side of the abdomen is the set of breathing 
organs, which have been mentioned heretofore. 

The larvae are found more particularly attached to sub- 
merged logs, wholly or partly submerged stumps, brush, 
bushes, and other like objects in the larger creeks and bayous 
of the region to which they are common. 




Fig. 211. — Simidium pecuarum: head of male at right; head of female 
at left — greatly enlarged. (From Annual Report of Department of Agri- 
culture, 188G.) 



When fully grown the larvae descend to near the bottom 
of the stream, sometimes eight to ten feet, to make their 
cocoons. 

The cocoon upon these leaves is conical, grayish or brown- 
ish, semitransparent, and has its upper half cut square off, 
more or less ragged, as if left unfinished. Its shape is irregu- 
lar, the threads composing it very coarse, and the meshes 
rather open and ordinarily filled with mud. They are not 
always fastened separately, but frequently crowded together, 
not forming, however, such coral-like aggregations as in some 
of the Northern species. The larva in spinning does not 
leave its foothold, but running in the centre of its work, uses 



FAMILY SI MV LI I Dm 265 

its mouth to spin this snug little house. In it, it changes to 
a pupa, which has its anterior end protruding above the rini. 

They remain in the pupa state but a short time. Both 
larval and pupal skins remain in the pouch for some time. 

The adult fly on emergence from the pupa rises quickly to 
the surface, and the wings expanding almost instantly, it 
darts away. 

The time of the appearance of the swarms is regulated by 
the earliness or lateness of the spring, and consequently it 
is much earlier in the southern parts of the Mississippi 
Valley. As a rule they can be expected soon after the first 
continuous warm weather in early spring. In 1885 the first 
swarms were observed in Louisiana March 11, in Mississippi 
and Tennessee May 1, and in Indiana and Illinois May 12. 

Horse Flies ( Tahanidce) . — Horse flies are pretty well known 
and quite important economically. They cause annoyance 
to domestic animals and to man. They are not credited with 
carrying any disease, but seem to be w^ell adapted to such a 
performance. They are aquatic in the larval stages so far 
as the larvae have been studied, and the larvae are carnivorous 
and seem to feed on a variety of aquatic life, dead or alive. 
They pass through pupa stages in the mud or deeper in the 
marshes of pools and ponds. The adults are very active 
and swift flying. The eyes occupy practically the whole 
head and are composed, especially in the males, of an enor- 
mous number of facets. The females are the biting members 
of the family, having the mouth parts much more fully devel- 
oped. The males live on plant juices, but probably do not 
feed extensively in the adult stage. The females seem quite 
blood-thirsty, though perhaps this is not a necessary food. 
The eggs are deposited in little clusters or masses on aquatic 
plants, usually just above the surface of the water, so that 
the larvae on hatching at once enter the water. The insects 
of this group are much more abundant where there is an 
area of water surface to provide the water habitat. The 
females gather to the water probably to secure water in con- 
nection with the deposition of the eggs, and a Russian ento- 
mologist proposed the plan of putting kerosene on the surface 



266 



ORDER DJPTERA 



of the pools to destroy the a(hilt females, and this seems to 
have been very successful. The trouble in this is that the 
kereosene kills other forms of life which are not obnoxious. 
There are several species in this locality. The species com- 
mon about horses are the green heads and the big black flies. 
The green heads sometimes cause a great deal of trouble. 

The remaining families of the order come in the suborder 
Cyclorhapha. This group includes an immense number of 
flies, many different families and some of the families an 
immense number of species. 




Fig. 212. — Tabanus atratus: a, larva; 6, pupa; c, adult. (After Riley.) 



The first important family in the group is that known as 
the SyrphidoB. This one family presents about as great a 
variety of life, habit and conditions as any in the order. 
There is everything from aquatic to arboreal species in the 
larvae. The rat-tailed forms which live in liquid have a long 
tube extending to the surface of the liquid. Another species 
occurs on trees. The more important economically are 
the ones that feed on plant lice, and these are a most impor- 
tant factor of control. Many species mimic members of 
other groups of insects. Some look very much like wasps, 



FAMILY OESTRIDM 



267 



others like bees, and the rat-tailed species {EristaUs tenax) 
looks like a drone bee. 

Bot Flies {Oestridoe). — The bot flies are parasitic in various 
mammals, occupying the body tissues and primarily the ali- 
mentary tract. The adults are bee-like, with rounded heads 
and small eyes, and are hairy. The antenna? are sunken into 
little pockets or pits in the front of the head, and the mouth 
])arts are aborted. The adults do not feed. The females are 




Fig. 213. — Horse bot fly (Gastrophilus eqiii): a, egg, enlarged; b, nat- 
iiral size; c, larva, newly hatched, enlarged; d, more enlarged; e, oral 
hooks; /, body spines; g, mature larva, twice natural size; h, adult female. 
(Author's illustration. Bur. Ent.. U. S. Dept. Ag.) 



the more commonly seen and they deposit their eggs on the ani- 
mals that are to serve as hosts for the larvae. The males gener- 
ally remain in shady places among grass, etc., so that they are 
much less likely to be observed. The larvae seem to have 
adjusted themselves to the parasitic condition from a more 
primitive condition, possibly that of living in organic matter 
of some kind. It seems most likely that some form with 
habits perhaps like the blow fly might in some cases deposit 



268 ORDER DIPTERA 

eg^s in siK'li ])la(*es tliiit the larvtie would survive and the 
liabit grachially acquired of hving within the liost tissues. 
They reacli maturity without destruction of the host form 
and the habit gradually becomes fixed. This habit is now 
definitely fixed among all the species of the family and 
they are restricted to mammals as hosts. Some infest the 
alimentary canal, some the nasal passages, some the tissue 
beneath the skin. The larvtie as parasites have undergone 
considerable modification from the primitive forms. They 
are usually provided with rows of spines or sharp spurs that 
assist their movements when they leave the host forms and 
for those that live in the alimentary canal there are hooks, 
modifications of the mouth parts, that serve to attach them. 
They may feed to some extent upon the secretion of the host, 
but most of the nutrition is absorbed through the body walls. 
The Horse bot fly {Gastrophilus equi) is one of the best 
examples and probably represents most nearly the primitive 
condition for the family. The adult occurs through the middle 
and last of summer and the eggs are deposited on the hairs of 
the horse, small yellow eggs glued very firmly to the hairs. 
In depositing the eggs the female darts toward the animal 
and thrusts the egg against the hair without alighting. The 
abdomen is thrust forward under the body. A glutinous 
secretion is discharged with the egg and binds and hardens 
almost immediately. The eggs are very thick-walled with 
chitinous walls and have a little operculum or cap at the end 
of the egg which is easily detached after a certain stage in 
the development. The time for hatching varies from three 
days to forty, but usually ten to fifteen days after deposition. 
Before that time they are hatched with a great deal of diffi- 
culty, and the larvae are rather inactive. x\fter fifteen to 
twenty days the activity begins to diminish. The majority 
die if not hatched in thirty to forty days. They do not 
hatch without the assistance of moisture, friction, and 
warmth to stimulate the larvae. With a little moisture and 
friction the cap slips off easily and the hooks of the larva 
fit it to attach itself immediately to the tongue or other part 
of the body of the horse. The egg shells remain on the hair 



FAMILY OESTRID^ 269 

after the hatching occurs. The time for the hatching of the 
eggs is rather important with regard to the treatment of 
the animal. It has been studied pretty carefully. Different 
statements as regards the period of incubation may mean 
different species observed. Egg deposition may go on until 
quite late in autumn, but is usually at its height about 
August or early September. The activity is retarded by cold 
weather and the larvae may survive longer then. The method 
by which they get into the stomach of the horse is by the 
horse licking itself or some other animal on which there are 
eggs. At first they are long and slender but after attachment 
in the stomach become thicker and fasten themselves by 
hooks to the stomach and remain there through late autumn 
and winter and early spring. They are sometimes very 
thickly set in the stomach of the horses. They must cause 
considerable interference with the activity of the stomach, 
and if massed together at the pyloric orifice may act as an 
obstruction. The effect on the animal is in some cases quite 
evident. The damage is doubtless different in different 
animals. The worst infested are those that have been in 
pasture. When they have completed their growth in the 
stomach they loosen their hold and pass out of the stomach. 
They burrow into the ground and pupate and remain in this 
condition several weeks — six or seven — and issue from mid- 
summer to early autumn. There is one generation a year 
and the longer period is spent in the body of the animal. 

Treatment for the larvse is rather severe. They may be 
killed with turpentine, but care must be used not to injure 
the horse by an overdose. The means of prevention are 
indicated by the life-cycle — condition of the egg and length 
of time it may develop. If eggs are removed every week or 
ten days there is no danger of serious infection. Horses 
curried regularly are not apt to be infested. They may be 
shaved off, and this is the most ready means of preventing 
the infection. Washes could be used to kill the larvae — 
kerosene, carbolic acid, etc. 

There are three or four species of this parasitic genus in 
the horse, but no other so common as Gastrophihis equi. 



270 



OUDKli DIPT ERA 



They cause a ^ood deal of annoyance. One is called the chin 
fly {GaMrophilnfi na.s'alis), which lays eggs on the jaws. 
Another, the red-tailed hot fly {(iastwphihis hwmorrhoidnlh), 
also deposits eggs in the vicinity of the mouth. 

Bot Fly of the Ox ( Ilypoderma lineaia). — The hot fly of the 
ox illustrates another method of development, but seems 
to have been derived from that of the one occurring on the 
horse. It is known in some parts of the country as the 
Texas heel fly. It occasions a great deal of loss to the cattle 




Fig. 2\^.—H ypoderma lineata: female — natural size indicated by side 
line. (From Insect Life.) 



industry. The larv&e perforate the hides. They develop 
under the skin and on maturing pass through the skin, 
leaving a lot of openings. Such hides are docked one-third 
in the market. Eggs are laid on the hairs of the legs, and as 
he found none on the hairs of the back, Dr. Curtice concluded 
that the larvae were taken into the mouth and travel by way 
of the esophagus and through the tissues of the thoracic 
region up through the tissues of the back as their normal 
route. The puncture is made after the larva is under the 



FAMILY OESTRID.^ 



271 




Fig. 215. — Hypoderma 6oi'is— enlarged. (After Brauer.) 




Fig. 216. — Piece of warbled hide — warbles about half size. (After 
Omerod.) 



272 



ORDER DIPTERA 



skin and some time before it is ready to issue. Tlie adults 
appear quite early in the season and the hirvse in the hacks 
of cattle are never seen until in the winter time — January 
first to ]\Iarch or April. They cause the muscles to have a 
jelly-like consistency. They injure the cattle in regard to 
growth and to milk conditions. The annoyance of the flies 



r .-A ^ 


b. 


/ \ 






i 






' 1 




: 





WfJ 



' )It 



i"4$'$f 




Fig. 217. — Hypoderma lineata: a, eggs attached to hair; b, c, d, dorsal, 
ventral, and lateral view of egg; e, embryonic or first larva, as seen in egg; 
/, fir, mouth parts of same enlarged; h, anal segments of same'still more 
enlarged. (From Insect Life.) 



when they deposit eggs and also the injury caused by their 
presence in the back of the cattle is in England estimated 
at about S5.00 a head. Eggs are attached to the hairs, and 
the larvae, according to Curtice, pass into the mouth and 
through the esophagus and through its walls into the adja- 
cent tissue and migrate by slow degrees to the dorsal portion 
of the body, finally reaching the subcutaneous tissue along 



FAMILY OESTRIDyE 



273 



the backbone, about six or eight inches from it and between 
the shoulders and the hips. The time of the appearance 
in that location and the time when the larvae are taken into 




Fig. 218. 



-Hypoderma lineata: ovipositor of female: a, from side; b, 
tip, from below — enlarged. (From Insect Life.) 





h 




I 




''^ c 


\ ] ' 




a 


d 



Fig. 219. — Hypoderma lineata: second stage of larva from esophagus: 
a, larva; h, enlargement of cephalic segments, end view; c, mouth parts; 
d, enlarged end view of anal segment, showing spiracles and spines. (From 
Insect Life.) 
18 



274 



ORDER DIRTERA 



the moiitli are separated by (juite a period. Curtiee claims 
to have found hirvie at all points between these two positions. 
This cannot be purely accidental. More recently an Irish 
investigator has reached the conclusion that the larvae bore 
into the skin and migrate to the wall of the es()})hagus from 
which point they travel to the position under the skin of the 
back. The adults emerge in early summer, in Texas as 




Fig. 220. — Hypoderma lineata: a, second stage of larva from back; 6 
and c, enlargement of extremities; d, ventral view of third stage with 
details of extremities at e and /; g, dorsal view of mature larva wnth enlarge- 
ments of anal spiracles at h; i, the same, lateral view. Natural size indi- 
cated by side lines. (From Insect Life.) 



early as May, in northern States May or June. The larvae 
are pretty well grown by February, and by early March they 
have practically reached maturity and the grubs issue 
during March and early April, drop into the ground and 
pupate and remain in this stage for five, six,, or seven weeks, 
and the adults come on from INIay to early June or the first 
of July. 
The European species which has now been studied with 



FAMILY T AC HI N I DM 275 

special reference to its mode of introduction is believed to 
follow the same method, but Miss Ormerod persisted in the 
belief that the eggs were deposited on the back and that the 
larvae bored through the skin, and claims to have seen chan- 
nels through the skin through which the larvse travelled. It 
is not likely that there would be this difference in the two 
species. This species causes a great deal of loss in the old 
world. The one method available for controlling either of 
these species is the destruction of larvse during the late 
winter and early spring when they are conspicuous along 
the back, and the method of extermination of the species 
would be to have all animals examined and all the grubs found 
destroyed. This is feasible theoretically, but impossible 
practically. They do not migrate far, and any stock owner 
can by close attention secure a large measure of immunity 
for his own herd. Cooperation would secure a more extended 
extermination. 

Siieep Bot Fly {Oestrus ovis). — The sheep bot fly illustrates 
another method of development. It deposits eggs or newly 
hatched larvae in the nostrils of sheep and these work their 
way up the passages. This entrance occurs during summer 
time and the development of the larvae goes on through fall 
and the larvae work their way back in spring and pupate in 
the ground and the flies issue in midsummer. They cause 
the greatest irritation and most serious symptoms occur 
during the time the larvae are w^orking themselves back. 
The sheep sneeze, etc., and sometimes show a dizziness or 
stagger. They may be cut out of the frontal sinuses but the 
cost of the operation is too great for general use. Preven- 
tion consists in avoiding the deposition of eggs in the nos- 
trils. Applying tar to the noses is one method, and another 
method is by furnishing plowed places or dusty places so that 
the sheep can bury their noses when the flies try to deposit 
eggs, or by giving the sheep a shed, as the flies are active 
in the sun and not in the shade. 

Family Tachinidse. — The family Tachinidce has a very 
important economic position on account of the large number 
of species that are parasitic upon destructive insects. The 



276 



ORDER DIPTERA 



adults appear much like the house flies or the stable fly but 
have usually numerous prominent bristles and spines, the 
bristles (arista) of the antennae lack the fine hairs which are 
characteristic of most of the Miiscidoe. 

These insects show some very striking adaptations in their 
parasitic life, some of the species depositing their eggs 
directly upon the bodies of the caterpillars which are to be 
the hosts of the larvae. The larvse on hatching bore at once 
into the caterpillar and develop within its tissues. In cer- 



^--=^ 




Fig. 221. — Euphorocera claripennis, a parasite of the alfalfa caterpillar: 
adult and enlarged antenna of same; puparium — enlarged. (From Howard, 
Bur. Ent., U. S. Dept. Ag.) 



tain species the eggs are laid upon the leaves and depend 
for their entrance to a host insect upon th^ leaf being eaten 
by some herbivorous form and in this case it would seem as 
if there would be some chance of the eggs being crushed or 
the larvse being destroyed in the process of swallowing. In 
one rather remarkable form the eggs are evidently deposited 
within the burrows of wasps which are stored Avith spiders. 
The TachinidoB follow the wasps as they drag their victims 
to the burrow and when the wasp enters they no doubt 



FAMILY MUSCID^E 



277 



deposit their eggs upon the spider, the larva feeding upon 
the food intended for the wasp larva or possibly upon the 
wasp larva itself. 

The typical Muscid flies (Muscidce), house fly, blow fly 
screw-worm fly, all live in organic matter in a state of decay, 
and all of them show very rapid rate of development, the 
larvie acquiring their growth in a few days' time, though 
longer time is usually passed in the pupa stage. The adults 
may live for a long time. House flies, for example, conceal 
themselves about houses and survive the winter, possibly 
also as pupse, and deposit eggs which start the summer 





Fig. 222. — Common house fly (Musca domestica): puparium at left; 
adult next; larva and enlarged parts at right. All enlarged. (After Howard, 
Div. Ent., U. S. Dept. Ag.) 



generations which follow each other with a great deal of 
rapidity. Twelve to fifteen days is all that is required for 
the complete cycle of many of the species. They are scaven- 
gers and in this may be looked upon as beneficial. They 
present also certain dangerous aspects as carriers of disease, 
especially typhoid, and deserve all the opposition they are 
receiving. 

The screw-worm fly deposits eggs occasionally in the 
nostrils of individuals, and in the case of wounds of animals 
the larvse work into the living tissue. It causes losses in 
cattle industry in the South. 



27S ORDER DIPTERA 

The house fly (Miisra dottiest lea) is i)erhaps the most 
universal, and oeeurs wherever civilization extends, and 
presents an important feature in its possibilities of carrying 
disease germs. One of the first cases establishing this con- 





'%:^') 


'^^n 


k 


'1 


^ 
^ 


CL 





Fig. 223. — The common house fly: a, full-grown larva; 6, one of its 
anterior spiracles; c, antenna; rf, hind end of body showing anal spiracles; 
e, side view of head; /. head from above; q, head of young larva; /?, eggs. 
All enlarged. (From Howard, Div. Ent , U. S, Dept. Ag.) 

nection was that determined during the Spanish- American 
war, where the source of the typhoid was traced to house flies. 
It is known to serve as a carrier for tuberculosis, dysentery 
and other diseases. Flies breed in filth, especially horse 
manure, the eggs requiring a few hours to hatch, the mag- 



FAMILY MUSCID^ 279 

gots from four to six days to grow, and pupation six to eight 
days, so there may be many generations in a summer. Pro- 
tection may be readily gained by community efi'ort. Their 
flight is sufficiently restricted to make individual effort on 
a farm well worth while, even if some nearby farms are neg- 
lected. 







# -b<^ 


-*\ 








1 


s^ <^ 


m 


J 




iH 


f 


v.: 


<3L 




-5 



Fig. 224. — The common house fly: a, pupa removed from puparium; 
b, hind end of body of larva in second stage; c, anal spiracles of larva in 
fiist stage. All enlarged. (From Howard, Div. Ent., U. S. Dept. Ag.) 

Horn Fly (Hceviatohia serrata Rob.-Desv.). — In the intro- 
duction and rapid spread of this insect we have an excellent 
illustration of the importance of giving attention to the 
injurious insects of other countries and of taking all possible 
means to prevent their importation. 

The species in hand has been a common insect in Em-ope, 
and with other members of the same genus recognized as a 
troublesome insect, though apparently no careful study of its 
life history has been made there. 



280 ORDER DIPTERA 

It was first noticed as troublesome to cattle in this country 
in 1887, and while we cannot say with certainty just when 
it was introduced, we may be pretty sure that it was during 
the year 1886, or at most not earlier than 1885. It is even 
possible that it may have been brought over in the spring of 
1887, as its powers of reproduction are such that a few weeks 
would suffice to make it a conspicuous pest 'in a limited 
area. 

Within two years from the time it was first recognized in 
serious numbers it had become so numerous and had spread 
over so large a region that it w^as made the subject of a 
very careful and successful study by Messrs. Howard and 
Marlatt of the Division of Entomology. The results of 
these investigations were published in Insect Life (vol. ii, p. 
93) and in the Annual Report of the Commissioner of Agri- 
culture for 1889. 

As to its introduction and spread in America, all accounts 
agree in placing the first serious occurrence of this insect in 
the vicinity of Philadelphia, and it appears probable that 
it was at that port that the flies first landed. 

From there as a centre it spread in all directions, though 
at first mainly southward, and by 1889 it had covered most 
of the State of New Jersey, portions of eastern Pennsylvania, 
a considerable area in Maryland, and also a portion of 
northern Virginia. 

In 1891 it had been reported from New York, Ohio, Ken- 
tucky, Georgia, Florida, and Mississippi, and in 1892 from 
Connecticut, Massachusetts, Canada, Michigan, Indiana, 
Iowa, Louisiana, and Texas. 

The adults of the horn fly are about half as large as the 
common house fly and very much like it in shape and color. 
The accompanying figures will serve to distinguish it. The 
larval stages are passed in from four to six days. 

The pupa stage may last from five to eight or ten days, so 
that the full time from egg deposition varies from ten to 
seventeen day s, estimated for the average as about two weeks. 
As the flies doubtless begin laying soon after issuing from 
the pupa stage, there is room for a number of generations 



FAMILY MUSCIDjE 



281 



during even a northern summer, probably from six to eight 
being common. 

For the destruction of the larvae, which is probably the 
most effective way of preventing damage, two principles 
have been established. The first involves the killing of the 
maggots by introduction of some destructive agent; the 
other, the prevention of their maturing by the rapid drying 




Fig. 225. — Horn fly (Hematobia serrata): a, egg; h, larva; c. puparium; 
d, adult in biting position. All enlarged. (From Riley and Howard.) 



of the mass of dung which supplies their food. The use of 
lime, as originally suggested in bisect Life, is a very effective 
plan, and where not prohibited by expense, should be generally 
adopted. Prof. Smith's suggestion to spread out the drop- 
pings of manure so that they may dry rapidly is applicable 
during dry weather and in some localities is accomplished by 
drawing brush across the fields, a method which must 



282 



ORDER DIPTERA 



necessarily fail to })e c'()in])lete in its ojx'ration, bnt much less 
expensive than the use of a shovel by hand. 

The Stable Fly {Stovioxys cakitrans, Linn.). — The stable 
fly is a well-known species which is widely distributed and a 
familiar pest in many countries. Its bite is severe and it 
causes a great amount of annoyance to cattle, horses and 
other domestic animals, and is frequently very troublesome 
to people working in places where it abounds. It is not 
confined to stables or to the quarters of domestic animals, 
but occurs frequently in shady places, groves and in dwell- 




FiG. 226. — Stomoxys calcitrans: adult, larva, puparium, and details — all 
enlarged. (From Howard, Div. Ent., U. S. Dept. Ag.) 



ings, especially in cloudy weather, and puts the occupants 
to great inconvenience. Its bite is not poisonous, and aside 
from the pain given and the possibility of it disseminating 
disease, it is less injurious than some other members of the 
group. When abundant, however, this annoyance may be 
very great, and they all deserve attention. Indeed, it is 
especially charged against this species that they have been 
the means of transmitting glanders from diseased to healthy 
horses, and anthrax among cattle, a charge which appears 
very reasonable from the fact that it inflicts a deep bite and 



FAMILY MUSCIDM 



283 



does not gorge itself at a single animal, but may fly from 
one to another in securing a meal. 

In late years it has come into especial prominence as a 
a carrier of disease. It was at one time thought to be the 
carrier of infantile paralysis but this relation has not been 
substantiated. 




Fig. 227.— Muscina stabulans: a, larva; b, head below; c, head, side 
view; d, thoracic spiracle; e, stigmatic plate; /, female; g, head of female; 
h, mouth parts; i, antenna. All enlarged, d, e, h, i, greatly enlarged. (Bur. 
Ent., U. S. Dept. Ag.) 

Tsetse Flies. — The tsetse flies have been notorious for a 
long period as extremely serious pests in parts of Africa 
and were described by early explorers because of heavy loss 
to domestic and wild animals. In recent years these have 
been connected with the transmission of certain kinds of 
diseases, and are now looked upon as having a most impor- 
tant bearing from the medical standpoint. 

The species longest known, Glossina morsitans, has been 
especially connected with loss among cattle, and horses. 
Glossina palpalis which has been determined as the cause 



284 



ORDER DIPTERA 




Fig. 228. — Glossina palpalis ( X 3f), the carrier of the trypanosome of 
sleeping sickness. (Bruce.) 




Fig. 229. — Phormia terroRnovoe — enlarged. (Howard, Div. Ent., U. S. 
Dept. Ag.) 



FAMILY MUSCID^ 285 

of sleeping sickness in man has received perhaps the greater 
attention in recent years. 

It can easily be seen that the introduction of either of 
these species into this country or even into South America, 
with the opportunity for further distribution would be a 
most serious menace, as there would be every possibility of 
the introduction of the diseases which are associated with it. 
These are perhaps examples of insects which deserve most 
careful attention from the stand-point of possible exclusion, 
and every effort made to learn their habits in detail and to 




Fig. 230. — Lucilia coesar — enlarged. (Howard, Div. Ent., U. S. Dept. Ag.) 

avoid such means of transportation as might possibly serve 
to transfer them to this country. It is reported that such 
an introduction has occurred in Australia. 

Blue-bottle Fly {Lucilia ccesar). — The blue-bottle fly is 
another species which is very abundant and almost uni- 
versally distributed. Its attacks are made upon any avail- 
able fleshy material such as carcasses of dead animals, fish, 
and so on. The female deposits eggs on living animals that 
have bruises or wounds or attractive points for deposition. 
Sheep are especially subject to attacks of this sort. The 
maggots of the flies do not limit themselves to the external 



280 



ORDER DIPTERA 



parts but ])urr()w into the flesh and may perhaps cause very 
serious injury. 

The meat fly or blow fly is another species that falls in 
the same group with regard to its habits, and against which 
it is important to protect domestic animals. 

Flesh Flies {Sarcophagidcp). — Flesh flies are quite familiar 
objects around houses, especially if there is any exposure of 




Fig. 231. — The green-bottle fly: a, egg masses in cow dung; 6, hatched 
egg; c, a portion of the egg surface seen under the microscope; d, unhatched 
egg; e, larva. All enlarged except a. (From Ann. Kept., U. S. Dept. Ag., 
1890.) 



fresh meats to attract them. The eggs are laid on meat by 
preference and hatching occurs within a very short time, in 
fact in some species it is stated that larv^ are extruded from 
the adult. Aside from their deposition upon meats, how- 
ever, there is often a deposition upon fresh wounds or abra- 
sions so that the larvae may make a serious attack upon 
domestic animals or even human beings, if there is an oppor- 
tunity for the attack. As a protection against this kind of 



FLESH FLIES 



287 



injury it is important that all bruises or scratches should 
be treated promptly so that domestic animals will not serve 
as an attraction for the species. 




Fig. 232. — Homalomyia brevis: female at left; male at centre, with 
antenna enlarged; larva at right. All enlarged. (Aftei Howard, Bur. Ent., 
U. S. Dept. Ag.) 




Fig. 233. — Apple maggot (Rhagoletis potnonella) : a, adult; b, larva or 
maggot; c, funnel of cephalic spiracle; d, puparium; e, portion of apple 
showing injury by maggots; a, b, and d, enlarged; c, still more enlarged; 
e, reduced. (After Quaintance.) 



In the genus Brosoyhila are a number of species, the 
pomace flies" which feed principally upon decaying fruits. 



288 ORDER DIPTERA 

They are perhaps of sHght economic importance as they do not 
attack growing plants, but on account of the great ease with 
which they may be bred in captivity they have been the 
basis of some most important investigations concerning the 
transmission of hereditary, characters. 

Another species is one that occurs as a pest in apples and 
is known as the apple maggot {Rhagoletis pomonella) , which 
diflFers in its method of work from the codling moth larvae 
in that the larvae work near the skin and make tunnels 
through the apple. It punctures the skin and deposits eggs 
inside. This goes on during the summer and the larvae 
mature in autumn with the maturing of the fruit. They 
hibernate as pupae. This species occurs now and then in 
Ohio, but is not so universally common as the apple worm. 
It is more distinctly a northern species, sometimes a serious 
pest in New England and parts of the States and Canada 
bordering on the Great Lakes. 

Family Hippoboscidae. — The family Hippoboscidce includes 
sheep ticks, and forest flies. They have the wing structure 
of the Diptera, suctorial mouth parts, but a very remarkable 
method of reproduction. Instead of extruding eggs, they are 
retained in the oviducts and developed through the larval 
stage, being nourished by nutritive fluids. They are not 
extruded until they are ready to pass into the pupa stage. 
They take no nutriment as pupae after leaving the oviducts. 
There is no food taken until as adults. There is an adapta- 
tion for the parasitic habit. This is a different sort of adapta- 
tion than is found in any other group of Diptera except the 
succeeding group. They are different from any other group 
of animals. 

Sheep Tick (M.elophagus oviniis, Linn.). — The sheep tick is 
a common pest of sheep. It differs from the most of the 
other members of the family in never possessing wings. The 
head is small and sunken into the prothorax. The middle 
portion of the prothorax is rather slender, contrasting with 
the development of this region in the winged forms. 

It is of a reddish or gray-brown color, about one-fourth of 
an inch long, and easily detected when present in any num- 



ORDER SIPHONAPTERA 289 

ber on sheep. They never migrate from the original host 
except it be to attach to another animal of the same species, 
and probably the principal movement is that which occurs 
after sheep are sheared, when the ticks tend to migrate to 
lambs. On the sheep, if abundant, they may cause con- 
siderable damage, indicated by lack of growth or poor 
condition, and when massing upon lambs they may cause 
great damage, resulting in the death of the victims if not 
promptly relieved. 

They are distributed over the world generally where 
sheep are kept, and are too well known by sheep breeders 
to make it necessary to emphasize the injury they may 
cause. All breeds of sheep seem alike subject to attack, 
but I know of no record of their occurrence upon other 
animals. 

While the ticks may be greatly lessened in number by the 
vigorous use of pyrethrum — a most available remedy during 
winter — the most practical plan to adopt, and one which if 
thoroughly followed will make all others unnecessary, is to 
dip the sheep each year after shearing. 

A flock once freed from the pests will not be again infested 
except by the introduction of infested animals: hence care 
should be taken in making additions to the flock to free the 
newcomers from parasites. It is also well to keep the sheep 
for a few days after dipping in a different inclosure from 
that occupied before, to avoid possible infestation from any 
stragglers that may have been caught on wool upon posts 
or brush, and if the wool is charged with them when clipped, 
it should be stored where the ticks could not easily return to 
the sheep. The ticks cannot travel any distance inde- 
pendently, and will soon die when removed from the sheep, 
and proper care here will insure success. 

Order SIPHONAPTERA. 

Another order is the Siphonapfera, The fleas are wingless 
or have the wings so aborted that they are practically wing- 
less. Vestiges of wings may occur but are useless as organs 
19 



290 



ORDER SIPHONAPTERA 



of locomotion. The adults have suctorial mouth parts and 
puncture various kinds of animals, sucking the blood for a 
food supply. The larvae are slender and live in refuse and 
rubbish, litter of dog kennels, etc., and when mature change 
to a very distinct pupa stage and then to adult flea. The 
pupa stage is like the adult in shape but the legs, etc., are 
encased in the rigid pupa case. The hindlegs are specially 




, Fig. 234. — Cat and dog flea (Ctenocephalus canis): a, egg; b, larva in 
cocoon; c, pupa; d, adult; e, mouth-parts of same from side; /, antenna; 
g, labium from below; b, c, d, much enlarged; a, e, f, g, more enlarged. 
(After Howard.) 



developed and their mode of progression is by leaping. 
They occur on different kinds of animals, as the dog and cat, 
and there are species that occur in houses, on squirrels, 
rats, mice, and various mammals. It is mainly on the 
smaller species of mammals, and one species occurs on birds. 
One species attacks poultry. It buries itself in the skin 
something like a jigger, though not so extreme in the extent 
to which it will burrow. 



CHAPTER X. 
BEES AND WASPS. 

Order HYMENOPTERA. 

The Hymenoptera are in some respects the culmination 
of the group of insects. They are speciahzed in several ways 
but the species are all characterized by having the mouth 
parts developed into both biting and sucking structures. 
In some respects they seem more specialized than all other 
orders and in some respects they seem less specialized than 
the Diptera and Lepidoptera. As a matter of fact in the 
evolution of the groups of insects there are several orders 
that must be looked upon as having evolved along divergent 
lines at the same time and none can be said to really outrank 
the others. The Coleoptera, Diptera, Lepidoptera, and 
Hymenoptera, all have a high degree of specialization. It 
is better not to try to consider them as in the line of a series 
of steps running up, but as parallel or divergent branches 
from a general trunk, all of them extending to extreme 
distances from the primitive stock. 

The Hymenoptera have four wings, and these are provided 
with rather few veins and pretty highly specialized in the 
venation, and in a few groups the veins are practically 
reduced to nothing. The mandibles are present for the most 
part in the adult forms but are almost lost in some forms that 
are fed by the adults in communal forms. They are both 
mandibulate and haustellate. The larvse are usually footless, 
fleshy, grub-like animals which depend on their food being 
supplied for them in one way or another and are incapable 
of moving about and securing their own food supply. This 
represents a high degree of specialization and reaches its 

(291) 



292 BEES AND WASPS 

culmination in the community habit of ants and bees. In 
no otlier group except the white ants is there such develop- 
ment of the community habit. 

The pupa stage is generally included in the nest or cells 
formed for the larval stage, and the forms are seen to be 
quite highly specialized when the cocoon is cut open. The 
larvae moult but the moults are not so conspicuous as in 
exposed forms. The group exhibits quite a variety of 
habit, some leaf -eating forms, some wood-boring forms, 
some that develop in galls, many that are parasitic inter- 
nally on other insects, and many store food in their nests, 
such as spiders, caterpillars, etc. These are sometimes 
stored in the ground, sometimes in mud cells, sometimes in 
channels in the wood, sometimes in paper cells. 

There are two large divisions, the Phytophaga, leaf-eating 
or plant-feeding free caterpillar-like forms, and the Aculeata 
which represent the other forms of the group, the larvae of 
which are dependent on a food supply provided by the adult. 
The adults of this group have a sting. 

The group Tenthredinidos is a large family of leaf-eating 
and gall-making insects and the typical ones being the 
willow saw fly and the gall-making willow forms. 

The willow saw fly {Cimbex americana) is one of the largest 
species that we have. The adult is steel blue, the wings 
smoky. It is quite conspicuous and lays its eggs on the 
leaves of the willow along the midrib and principal veins of 
the leaf. The larvae hatch in a few days and grow during 
the midsummer and are noticed as large yellow caterpillar- 
like forms clinging to the twigs and leaves of willow par- 
ticularly or sometimes also to elms and a few other kinds of 
of trees. Some of the larvae have a prominent black dorsal 
line. They coil themselves quite a little especially when 
resting. While feeding the body is stretched out and they 
cling by means of the prolegs of the abdomen as well as by 
the thoracic legs. Prolegs are similar to those of the cater- 
pillar. There are certain similarities with some of the very 
generalized Lepidoptera and the prolegs might possibly be 
taken to indicate some affinity. However, it is probably 



ORDER HYMENOPTERA 293 

better to look upon it as an independent development of a 
similar structure based on similar habit. The number of 
prolegs varies from twelve to sixteen. There are twenty-two 
legs altogether. The' saw fly larvse become fully grown by 
the latter part of the summer and secrete themselves near 
the surface of the ground, generally among dead leaves and 
rubbish. They spin a quite strong silken cocoon with a 
papery texture, somewhat more dense than is common for the 
caterpillars of the silk-making moths. In this cocoon they 
remain as larvse for quite a period. They finally pupate and 
the adults issue in the spring and deposit eggs so as to 
produce the summer generation of willow worms. They 
become of economic importance where the shade trees they 
feed upon are of importance — willow trees, elm, etc. They 
are parasitized and the cocoons are eaten by mice and so 
kept down generally to a moderate number and are not 
usually very destructive. 

The pear slug {Eriocampoides limacina) occurs quite 
commonly in orchards and attacks not only the pear, from 
which it dervies its name, but also apple and other orchard 
trees. The larva has a strict resemblance to the mollusks 
called slugs, as the body is covered with a dense slimy secre- 
tion which hides the segmentation and external features of 
the body. They feed upon the surface of the leaves, just 
leaving ribs and veins. The trees attacked often have the 
appearance of being scorched by fire. 

They are best treated by the application of arsenical solu- 
tions, applied as soon as their work appears. 

The American rose slug (Endelomyia rosce) is frequently 
troublesome in its attacks on the leaves of rose bushes which 
are stripped or skeletonized so that the bushes are rendered 
quite unsightly. 

Arsenical solutions can be used, or if these are not desired, 
hellebore may be used for their control. Other species 
affect gooseberry, strawberry and other such crops. Many 
instances being of considerable importance. 

The Uroceridoe are wood- or stem-boring species and 
more specialized than most of the preceding family. 



294 



BEES AND ll'yl,SP.S' 



One form is particularly interesting, Tremex cohimha, or 
horn tail or pigeon tremex. It has a rather peculiar shape 
both in the larval and adult stages. The adult is an inch 
or more in length and with a prominent ovipositor which 
extends back about one-half inch from the back of the 
abdomen; both larvje and insects are cylindrical, the result 
of the boring habit. These adults appear in summer and 
deposit eggs on the bark of different kinds of forest trees — 
sycamore, maple, and others. The larviie burrow in, form- 




FiG. 235. — Pear slug: a, adult saw fly, female; h, larva with slime 
removed; c, same in normal state; d, leaves with larvae, natural size; 
a, b, c, much enlarged. (From Marlatt, Div. Ent., U. S. Dept. Ag.) 



ing tunnels through the heart wood pretty well down into 
the tree. Sometimes the trees are extensively perforated. 
Boring continues in through the tissue of the wood till they 
get their maturity and then they burrow out through the 
bark. Pupae are formed in the burrow near to the surface 
of the tree and the adult works its way out from the cocoon 
after the pupa is split open. Occasionally the adults will 
be found with the ovipositor fast in the bark of the tree 
or in the wood. They burrow in to deposit eggs and seem 



ORDER HYMENOPTERA 295 

unable to withdraw the ovipositor. Presumably they 
deposit a single egg in each perforation. There are two 
common parasitic species, Thalessa atrata and limator, 
which are the natural check upon the multiplication of this 
form and which ordinarily keep its numbers down to narrow 
limits. Without this check the species would probably mul- 
tiply .to a great extent. The parasites are representatives 
of another family, IchnewnonidoB. They are rather slender- 
bodied and with extremely long ovipositors. In Thalessa 
atrata they are four or five inches long. These are driven into 
the burrows of the tremex and the eggs are deposited in the 
burrow and presumably at some point close to the tremex 
larva. The larva of the Thalessa is said to attack the tremex 
larva externally and not to be internally parasitic— a little 
variation from the general habit of parasitism for the family. 
Cynipidse.— The Cynipidoe are in one sense a vegetable- 
feeding group, though some are hosts or guests of gall-makers. 
The primary feature is that they make galls and the larvse 
develop within these galls. Galls are not a normal plant 
product, nor a product of the insect alone, but a combma- 
tion product of the insect and the plant. A stimulus given 
to the plant cells results in a definite specific form of growth 
which is just as specific as the form of the leaf or the fruit 
of the plant on which it is formed. Species can be deter- 
mined accurately from the form and structure of the gall. 
The most familiar of these galls are the oak apples. These 
are rich in tannic acid which gives the gall a decided flavor. 
A globular structure is built out by a great growth of plant 
cells. The gall grows and develops more rapidly than the 
larva. The larva gets its growth by eating the cells which 
are close to it and all the rest of the structure is apparently 
developed purely as a protective device for the larva. 
The greatest number of species occur on oaks, some on 
roses, etc. There are dozens of different kinds on oaks and 
many different species on a single species of oak and some 
restricted to one certain species of oak alone. 

Parasitica includes several f amihes : IchneumonidcB, a large 
group ; Braconidoe; Chalcididw, a large group ; and Proctotrupid(B. 



296 BEES AND WASPS 

All of these are distinctly parasitic in habit. BraconidcB 
and IchneumonidcB are the more generalized kinds of para- 
sites and parasitize such forms as the caterpillars of the 
Lepidoptera in immense numbers. They constitute a very 
important check upon a number of very important species. 
It is hard to do much in the way of encouragement of them, 
though they may be transported from one country to 
another. One subfamily is pretty commonly parasitic on 
plant lice. 

ChalcididcB form a specialized group with much reduced 
venation for the wings and the Proctotrupidce are minute 
and largely egg parasites. 

Family Ichneumonidse. — The Ichneumon flies include 
many of the larger species of parasitic Hymenoptera and a 
number of species which have important economic bearing 
on the abundance of destructive species. Good examples are 
to be noted in the species of Thalessa which parasitizes the 
pigeon tremex and in species of Ophion which attack a num- 
ber of different kinds of caterpillars. The species of Pimpla 
are also conspicuous members of the group and their attacks 
are made especially upon injurious species of moths, so that 
they are to be counted distinctly serviceable. 

Pimpla conquisitor is one of the parasites of the tent cater- 
pillar and it is possibly due to this species that the tent 
caterpillar is less destructive than it otherwise might be. In 
this species the parasite lays its eggs in the cocoon of the 
host and its larva develops within the pupa, so that it 
serves to prevent the development of the adult and the 
deposition of the eggs which would follow. 

Family Braconidse. — The family Braconidoe is quite similar 
to the preceding but the species are on the average smaller 
and many of the species parasitize the minuter kinds of 
insects such as plant lice. A quite common species is Apan- 
teles glomeratus which is a parasite of the common cabbage 
worm and which no doubt serves as a quite important factor 
in assisting to keep this pest in check. 

Perhaps one of the most important species is the little 
Lysiphlehus tritici which is a very abundant parasite of 



ORDER HYMENOPTERA 



297 




Fig. 236. — Pimpla conquisitor, an important parasite of the tent cater- 
pillar: a, larva, enlarged; b, head of same, still more enlarged; c, pupa; d, 
adult female, enlarged; e, f, end of abdomen of adult male, still more 
enlarged. (From Fourth Report, U. S. Ent. Con.) 




Fig. 237. — Apanteles glomeratus: a, adult fly; 6, cocoon; c, flies escaping 
from cocoons; a, b, highly magnified; c, natural size. (After Chittenden, 
Div. Ent., U. S. Dept. Ag.) 



298 



BEES AND WASPS 



aj)hi(ls. It is a miiuito sj)ecies and its larva maintains its 
entire growth witliin tlie body of an aphid, the entire eon- 




FiG. 238. — Parasitized cabbage worm (Pontia rapce), showing cocoon 
mass of Apanteles glomeratus below. (From Chittenden, Div. Ent., U. S. 
Dept. Ag.) 




Fig. 239. — Lysiphlebus trilici, principal parasite of the spring grain aphis: 
adult female and antenna of male, greatly enlarged. (Webster, Div. Ent., 
U. S. Dept. Ag.) 



ORDER HYMENOPTERA 



299 



tents of which are not equal to a drop of water. However, 
the parasite may feed upon the aphid during some httle 
time and is supplied with food from the efforts of the aphid 




Fig. 240. — Wingless female of "green bug" containing larva of the 
parasite Lysiphlebus tritici. Much enlarged. (Webster, Div. Ent., U. S. 
Dept. Ag.) 



sucking nutriment from the plant. This species is consid- 
ered one of the principal agents in control of the spring grain 
aphis or the "green bug" which during recent years has 




Fig. 241. — Lysiphlebus depositing its eggs in the body of a grain aphis. 
Much enlarged. (Webster, Div. Ent., U. S. Dept. Ag.) 



caused extensive injury to the wheat crop in the south- 
western part of the country. Its attack seems to be dis- 
tributed, however, over a number of species and it is therefore 



300 



BEES AND WASPS 



able to maintain itself even in the absence of any one species 
of plant louse. 





Fig. 242. — Pteromalus puparum: female at left; male at right — highly 
magnified. (Chittenden, Div, Ent., U. S. Dept. Ag.) 




Fig. 243. — Chalcis ovata, a parasite of the alfalfa caterpillar: a, pupa; 
h, parasitized pupa of tussock moth {Hemerocampa leuco stigma) : c, adult; 
d, same in profile; e, pupal exuvium. Enlarged. (From Howard.) 

Family Chalcididae. — ^The family Chalcididoe, one of the 
groups which includes extremely minute insect forms which 
parasitize insects, such as the plant lice, scale insects, and 



ORDER HYMENOPTERA 301 

many other forms. They have broad heads, rather thick 
jaws and are quite generally of brilliant metallic colors. A 
distinctive character is found in the reduction in the veins 
in the wings so that only the costal vein borders the front 
margin of the wing and is so developed as to be rigid. In 
larger insects a great number of these parasites may develop 
in a single individual. In the smaller species usually a 
single parasite is found in the host. They are especially 




Fig. 244.— /sosoma tritici: adult of the joint worm— much enlarged. 
Howard, Div. Ent., U. S. Dept. Ag.) 

efi'ective in the destruction of scale insects, and some of the 
species are parasitic in the eggs of other insects. In some 
cases they become secondary or tertiary parasites in which 
case their value is changed. 

Pteromalus puparum, one of the parasites of the cabbage 
worm, is apparently distributed well over the area occupied 
by this species and its attacks upon the host form serve as 
one of the quite constant checks upon the abundance of that 
species. The parasitized pupse usually show a different 



302 



BEES AND WASPS 



color, and if observed these may be allowed to remain in 
the fields with the expectation of the ])arasite serving a 
good purpose for a later generation. If possible it is well 
to assist them somewhat by putting the pupae under screens 
which will permit the escape of the parasites, without 
allowing the escape of butterflies which might issue from 
healthy pupae. 

While most of these species are parasitic, there are a few 
which are plant feeders, and notable among these is the 




Fig. 245. — Bits of hardened straw remaining with the grain after 
thrashing. (After Webster, Div. Ent., U. S. Dept. Ag.) 



wheat joint worm {Isosoma tritici), which is the cause of a 
great deal of damage to wheat in many parts of the country. 
The presence of the joint worm is evidenced by the forma- 
tion of woody places in the stem, within which the worm 
is found and the effect of its injury is to cause the stems to 
become weakened so that frequently the grain will be broken 
down, especially if there are severe winds. The insects pupate 
within the stems and remain in the pupal stage all winter. 
This accounts for their frequently being found in chaft' or 



ORDER HYMENOPTERA 



303 



straw. Sometimes the hard pieces of straw are carried over 
in the threshing and mixed with the grain. It is evident 




Fig. 246. — Isosoma tritici: female ovipositing. (Photo by Ohio Exp. Sta.) 

that burning of the stubble in the fall or early spring will 
destroy the pupa in the fields and it is considered that the 
use of straw and chaff in the bedding of stock or as fodder 



304 



BEES AND WASPS 



is an excellent plan to reduce the infestation. Of course 
burning chaff or straw would accomplish the purpose, but 




Fig. 247. — Isosoma tritici: adult male. (Photo by Ohio Exp. Sta 




Fig. 248. — Isosoma tritici: larvae. (Photo by Ohio Exp. Sta.) 



this is not deemed necessary if the straw passes through the 
barnyard, as most of the pupae are killed by this treatment. 



ORDER HYMENOPTERA 305 

The egg parasites (Prodotrupidce) are extremely small, most 
of the species being parasitic in the eggs of insects. Eggs of 
web worms are parasitized and the whole development of 
the Proctotrupid is contained within the egg. One species 
is described as one-nintieth of an inch in length, another one 
one-himdred-and-fiftieth of an inch and the body very slender. 
These serve a most important function in the destruction of 
other insects, those that would otherwise hatch from the 
eggs. When the parasites feed on the caterpillars the damage 
is only partly checked, but when the parasite feeds on the 
eggs the damage is all prevented. One of the important lines 
of economic entomology is to study such forms and their 
life histories with regard to other species, as primary para- 
sites, secondary parasites, tertiary parasites, etc., since 
their value depends on whether they directly control a pest 
or whether as a secondary parasite they reduce the numbers 
of a primary parasite which is useful. 

Ants (Formicina) are one of the most interesting groups 
of insects. They are sometimes given the rank of a superior 
family, but the principal family is that called Formicidoe. 
The name is associated with the secretion of formic acid. 
The name of the group probably gave the name to the 
chemical. The secretion is one of the characteristics of the 
Hymenoptera. Ants present striking habits of family life; 
the formation of different classes among the individuals 
of a colony. This separation into classes is paralleled in 
other groups, as the bee family and among wasps, and 
expecially the termites. The result of community life is 
that it presents certain relations in the community in the 
way of division of labor. The primary forms are males 
and females, and then a class which are not sexual but are 
derived from a modification or suppression of the reproduc- 
tive factor in one of the sexes. Occurring with this is the 
reduction or complete absence of wings. These constitute 
the so-called workers or soldiers of a colony. They have no 
wings whatever. This feature reaches far back into the 
ancestry of the group, or else shows parallel evolution. 
Sexual individuals have wings primarily but in the case of 
20 



306 BEES AND WASPS 

tlie queens the wings are broken off or dropped off after the 
flight associated with mating. Then the females are unable 
to travel and remain fixed in a certain colony and furnish 
off'spring for the colony. A group of ants is called a formi- 
cary. It may vary in number of individuals from a few 
hundreds to thousands. A single queen ant may survive 
for a great number of years and the same colony may go on 
for many years. The usual course of the life-cycle is for 
winged females to issue from some colony and make their 
flight that is connected with mating, and then to burrow 
into the ground or select a suitable nest to place the eggs 
and begin the formation of a new colony. The fertilized 
queen is capable of producing workers and in some cases the 
queen alone wdll start a colony. In some forms perhaps the 
help of other ants is needed. With the starting of the 
colony and the deposition of eggs a colony becomes more 
populous. Differentiation has not gone quite so far in ant 
colonies as in some others. The workers take care of the 
eggs and the young and shift the young about, and if the 
nest is disturbed they carry the pupse to a place of safety. 
The pupae are, of course, helpless. The workers and soldiers 
die off pretty rapidly. They survive through the w^orking 
period and when they die are replaced by other workers. 
The colony retains its individuality year after year. The 
life of the colony is probably at least as long as the life of 
the queen and probably continues longer than that. Other- 
wise the colony w^ould have to terminate soon after the 
death of the queen. The multiplication of colonies is pro- 
vided for by the issuing of new queens from the colonies 
and the ability of the ant to survive depends as much on 
its ability to form new colonies as on new individuals. 
There is just as much reproduction of colonies as of indi- 
viduals. The cycle is probably for annual periods in each 
season and the females are probably produced annually. 
The food of the ants is primarily plant food. They collect 
nectar and various substances of vegetable origin, and the 
workers are responsible for the collecting and storing and 
using of the food supply. Indirectly they get such supplies 



ORDER HYMENOPTERA 307 

from the aphids. They store up grain in some instances, 
and use this grain to some extent at least as a food 
supply. 

One of the species — the honey ants — collect honey and 
store it in the stomachs of certain individuals of the colony. 
The bodies of these individuals become very much distended 
and the abdomen becomes large and spherical and these 
keep the food for a part of the year. This ant occurs in the 
plateau regions of Colorado, particularly in the Garden of 
the Gods. The volume by McCook on these ants is an 
especially interesting account of animal adaptation. Also 
Lubbock's book on Ants, Bees and Wasps gives many 
interesting experiments, but his observations indicated that 
while there is an adaptation to complex conditions they are 
not comparable to the activities of human beings. 

There are many species — little red ants, those occurring 
in gardens, and walks, the house ants, and the large car- 
penter ants, which form nests in hollow logs. The queen is 
quite a large insect and usually with wings entirely wanting. 
Large red ants and large black ants construct hills for their 
nests, sometimes three to six or eight inches high, and 
perhaps twelve to eighteen inches across the top. This red 
ant is a slave-making species, going out on forays and 
capturing black ants which they force to carry on the labor 
of the colony. Some species are said to have carried the 
slave-making habit to such an extreme that they are unable 
to get along without the slaves and even require slaves to 
go out and capture new slaves. 

Field Ants. — One of the important species is the little 
field ant which is associated with the corn-root louse and 
which has been named in connection with the discussion of 
the aphid. This species is very widely distributed through- 
out the United States and wherever corn is grown and the 
corn-root louse is present it constitutes an important factor 
in the abundance and destructiveness of the root louse. 

The Argentine ant {Iridomyrmex humilis Mayr) is one of 
the recently introduced pests and one which is liable to 
become distributed to cover the Southern States and possibly 



308 BEES AND WASPS 

to occupy at least the cotton-growing region if not a greater 
extent of the country. 

Tlie species is tliought to have been introcUiced from 
Argentina and was first noticed in New Orleans where it 
was reported as occurring in fair numbers in 1891. It is 
now known throughout most of Louisiana and in eastern 
Texas, and also occurs in California. Within the range of 
its distribution it has become a very serious pest and its 
further distribution will naturally be a matter of serious 
consequence to other localities. Without assistance the 
ant migrates slowly but with the opportunities afforded 
by commerce its dispersal may be quite rapid. 

As with the other ants there are males, females, and 
neuters; the males and females being winged, the neuters 
wingless but the females lose their wings after the mating 
flight. 

The size of the colonies varies from a few individuals to 
many thousands and a number of queens may be present 
in each colony. The nests are built in various places under- 
ground, seldom occurring at any great depth. 

This species is a most difficult one to control and experi- 
ments with poisonous materials, repellants, etc., have met 
with only partial success. 

Wasps {Siihecina). — In this group we have a considerable 
number of solitary forms of those which preserve the primi- 
tive conditions of males and females without workers or 
with large broods raised at one time in one nest. Mud, 
paper, pith, etc., are used as building materials. The sand 
wasp {Bemhecince) burrows into the sand for its nest. They 
stock these nests with insects of difterent kinds such as May 
flies. The larvae develop by feeding upon the bodies of these 
stored insects. It is strange that they can keep a burrow 
complete enough so that they can pass in and out a number 
of times. They are very common here and are protected 
to some extent by the coloration of the body. Their bur- 
rows are constructed along through the summer and the 
larvae develop during the summer and presumably all reach 
the pupa stage before winter and live over as pupse, issuing 



ORDER HYMENOPTERA 



309 



the following season. The adults will be found flying around 
all through the midsummer months. Perhaps they are a 




Fig. 249. — The Argentine ant, adult forms: a, adult male; al, head of 
male; a2, petiole of male; b, worker; bl, head of worker; b2, petiole of 
worker; c, fertile queen; cl, head of queen; c2, petiole of queen. All 
greatly enlarged. (After Newell.) 



310 BEES AND WASPS 

little more abundant in the later part of July. They belong 
to the Bcvihecidoe. One of the large members of the family 
is called the "cicada killer" Sphecius speciosus. 

Social wasps {Vcspidce) make large nests and large colon- 
ies and show some degree of differentiation into classes or 
castes of individuals in that there may be smaller indi- 
viduals at the end of the season which live through the 
winter. 

The Hornet {Vespa maculata) builds up a large paper nest 
which is made up of a series of combs with the aperture at 
the lower part. This becomes very populous during the 
latter part of summer. The survivors are adults that secrete 
themselves under leaves and rubbish and start a fresh 
colony the succeeding year. They do not live in the large 
nest through the winter. This common species is social. 

The yellow jacket {Vespa germanica) is also a social 
species, its nests are found in hollow^ trees. 

It is interesting to compare the materials used by these 
species. They use wood or paper which is a pulp worked up 
from the wood fiber and is to be compared with manufactured 
paper in the tissue of which it is made and in the manner of 
manipulation. 

In the bees, Apidce, there is an elongation of the beak for 
getting the nectar from the flowers and the more specialized 
forms secrete wax for the formation of the cells. This is 
worked up into a gum or built into cells for the rearing of 
the larvae. There is a gradual culmination in the develop- 
ment of community life in this family from the wild bees that 
are practically solitary up to the bumble bee and honey bee. 
The honey bee is probably the best-known because kept 
under domestication. A bee colony consists of a queen, which 
is a constant factor in the colony^a queenless colony can- 
not survive any length of time — and drones or males which 
occur during the summer. These are the normal-sexed indi- 
viduals. Then we have the workers or neuter forms which 
are undeveloped females and these carry on all of the com- 
plex work of the colony, providing food, caring for the larvae 
and for the rearing of new queens. 



ORDER HYMENOPTERA 311 

The cycle as applied to the queen would involve three to 
five years. They live that long and deposit millions of eggs 
during that time. The drones live but a short period. The 
workers live a few weeks or months through the summer 
and in the more inactive parts of the year. The queens from 
the egg stage to the adult stage occupy about sixteen days, 
the workers twenty-one days, the drones twenty-four days. 
There is a distinct difference in the eggs that produce workers 
and drones. The worker eggs are fertilized and the drone 
eggs are unfertilized. This is apparently controlled by 
the queen and dependent upon the kind of cells in which 
the eggs are laid. The exact method of control by the 
queen is not fully understood. The size of the cells may have 
some effect by the pressure on the abdomen. The accelera- 
tion of the queen may be because the workers feed them with 
a richer sort of food. They develop more rapidly and the 
reproductive organs are fully developed. There is colony 
reproduction as well as individual reproduction, that is, an 
increase in the number of colonies. They die off from old 
age, loss of queen, cold weather, etc., and if there were no 
process for increasing the number of the colonies they 
would be exterminated. This is provided for by swarming. 
The queen and a large number of workers issue from the 
colony and form a new colony. The old colony is provided 
for by other young queens in the cells or else fertilized. 
There is a loss of honey but no break in the life of the colony. 
Bee-keeping is an important industry and there are many 
books dealing with the subject. Among those of special 
value are the following: 

Cheshire, Honey Bee. Root, Bee-keeping. Langstroth, Hive and Honey 
Bee. Snodgrass, Anatomy of the Bee. Benton, The Honey Bee. Cook, 
Manual of Bee-keeping. Comstock, How to Keep Bees. PhiUips, Bee- 
keeping. Pellett, Productive Bee-keeping. 



riTAPTKU XI. 
PRIN( iri.KS OF ECONOMIC ENTOMOLOGY. 

\ViiiLK it cannot be assumed that we liave at present a 
C()ni])lete knowledi^e of tJiose underlying principles which 
are to be recognized in the prevention or control of insect 
ravages, enough has been done to make an attempt at a 
brief statement of such i)rinci])les in order. Many of these 
principles have been stated in greater or less detail in the 
writings of diti'erent entomologists but no c()mi)rehensive 
statement lias been attempted — especially since the marked 
advances of the past quarter- century. Applied entomology 
today is a totally different structure tlian that wliich 
existed twenty or even ten years ago. In many respects it 
is getting nearer to the fundamental laws of biology, and 
there is a more general appreciation that its successful appli- 
cation involves thorough acquaintance with biological prin- 
ciples. In tlie broadest sense economic entomology involves 
a recognition of the relation existing between insects and 
other organisms, but finally, the relation they bear to the 
human species. 

RELATION OF INSECTS TO OTHER ORGANISMS. 

Considering the great multiplicity of insect forms, their 
world-wide distribution in almost every condition open to 
the su])])ort of life, it is not strange they occupy a most 
imi)ortjint relation to other organisms. This relation may be 
serviceable or inimical, directly or indirectly from the 
stand-point of any particular organism, and may indeed 
differ totally at different times or under different conditions. 
From the stand-point of any particular species it is detri- 
(312) 



ECONOMIC ENTOMOLOGY 313 

mental if the insect feeds upon the plant or animal or inter- 
feres with its successful existence. It is beneficial, if it 
contributes to its success by warding off other dangers or 
assisting pollination or contributing in any way to its better 
growth and development. 



ECONOMIC ENTOMOLOGY. 

Economic entomology is based upon the relation of 
insects to mankind and all species that interfere with his 
welfare are considered injurious, and those that may serve 
him in any way are considered beneficial. The relation, 
however, may become very complex. An insect that feeds 
upon a cultivated crop, or destroys the products of a crop, 
or injures a domestic animal, or worries man himself, or 
menaces his health by inoculating him with disease, is 
injurious from the human stand-point. While if it produces 
a valuable material such as silk or honey, wax, dyes, etc., 
or serves to destroy injurious species as predaceous and 
parasitic forms, or feeds upon noxious plants, weeds, or dis- 
poses of noxious substances, as the scavengers, it is directly 
useful, and we term it beneficial. Many cases are very clearly 
in one class or the other; many have little apparent impor- 
tance one way or the other, and in many cases the relation 
may change with circumstances. For example, a parasitic 
insect preying on an injurious species is useful to us, but if 
it destroys a useful insect it becomes injurious. A parasite 
on a parasite, that is, a secondary parasite is detrimental if 
the primary parasite attacks an injurious insect, and a 
parasite upon this secondary parasite, that is, a tertiary 
parasite would be useful, since its effect would be to check 
the secondary and favor the primary parasite. Still further, 
a quaternary parasite, and this is I believe as far as this 
relation is known, would be injurious. The reverse in each 
case would be true if the original host were useful. 

We should not forget that these three terms refer strictly 
to mankind, for in the broader biological sense each kind of 



ril 1 i'h'i.\cn'Li^:s of economic entomolocy 

juiiinal is doing its host to ]HT])ctiint(' itsHf and nnilti])ly 
its kind, and t'\rr}' intorl'crcnct' is from its stand-jxiint 
injnrions. 

FOOD HABITS. 

It is very ovidtMit that ono of the first and most important 
relations t'oncrrniniij an insect is to he fonnd in its food 
liahits. 

Insects, like other animals, may he considered i)rimarily 
herhivorous. 'J'hat is, the most general ])lan of nutrition 
for them ^\•onl(l he to feiMl ni)on fresh, growing leaves of 
plants, with feeding iii)on fruits, seeds, hark, wood, roots, 
decaying wood as adaptations, while the assumption of car- 
nivorous hahits either as ])redaceous or parasitic species, or 
to go further, sucking hlood of higher animals may he 
considered adaptations in another direction. 

It is on this hroad, general hasis that we may consider 
herhivorous insects in the main injurious, and carnivorous 
insects, es])ecially if })re(laceousan(l ])arasitic on other insects, 
as heneiicial. 

In this connection we may refer to the principle which 
has been termed "unity of hahit" and treated hy Dr. B. D. 
Walsh. This is in elVect that in any given group we may 
expect to find similar hahits among all the s])ecies, and if for 
any s])ecies the hahits are unknown, they may he expected 
to follow those of the known species. To this law there may 
he striking exce})tion, however, and along certain lines 
peculiarities should he considered the rule and not the 
exception. To find the most certain action of the law we 
may, I think, say that in all particularly specialized groups 
"unity of hahit" is practically general. In less specialized 
grou])s variation is more frequent. For example, in the hark 
heetles, ScoIi/ti(hv, we would he astonished to find a leaf- 
eating larva, or in Aradidw a species that does not live under 
hark is excejitional. In Lcpidojifcra, the larval diet is gener- 
ally herhivorous and the two or three carnivorous species 
notahly the exception. We safely assume that all plant 
lice are ])lant feeders and treat them accordingly. The 



MEASURES FOR INSECT CONTROL 315 

weevils are reckoned invariably as plant feeders, almost 
entirely confined to fruit or seeds, while Carabidw, though 
largely carnivorous, show too much variation in food and 
too many herbivorous species to make it safe to draw con- 
clusions without the study of each species. In the applica- 
tion of this principle, therefore, it l)ecomes necessary to 
consider the nature of the group as a whole, not merely 
the habits of certain ones. 

MEASURES FOR INSECT CONTROL. 

There have been a great many difl'erent remedies and 
plans of treatment for the control of injurious insects and it 
would be impossible to discuss them all, even those which 
have general application, in a short course. The attempt 
will be to select some of the most universal and useful and 
give them with such rules as to make it possible to apply 
them without further instruction. 

In general the methods of control for insects may be 
separated into those which are direct and have in view the 
destruction of the insect with some destructive agent or 
mechanical application, and those methods that depend upon 
some plan of cultivation or sequence of crops to prevent or 
modify the insect attack. 

Direct Methods. Insecticides. — Substances used in such 
manner as to kill directly are termed insecticides, and insec- 
ticides may be classed broadly into two large groups: (1) 
those which are poisonous in character and depend for their 
effect upon the insects swallowing them with their food and 
(2) those which affect the insects by contact or penetration, 
such as the oils and fumigants. 

Of the poisonous materials some preparations that are 
among the most important may be mentioned. 

Paris Green. — Paris green is a bright green arsenical 
powder which should contain at least 50 per cent, arsenious 
oxide and not over 3.5 per cent, soluble arsenic. The for- 
mulae for its use are as follows : 

Paris green 5 ounces 

Lump lime 1 pound 

Water 50 gallons 



310 /'/;/.V(7/'/>/';n of fcoxomic estomolocy 

For small (luautitics list*: 

Paris urooii 1 hoa|)iii<; (easpooiifiil 

Lxnnp lime 2 or 3 ounroy 

Water 3 Rallons 

For dry application tlio powdoRnl Paris uriHMi may Uv 
mixed with llour or air-slaked lime and diistivl u|)on the 
plants by enclosing- tlu^ ]>o\vder in a mnslin sack and shaking- 
this over the plants it is desired to tn^it. 

London purple is a hy-prodiict in the manufaetnre of 
aniline dye and is an elVeetive poison hut somewhat less 
certain in its elVeet and more likely to injure foliajj^e. It is 
at ])resent not so eonnnon on the market as Paris i^nnMi. it 
is, however, somewhat cheaper and when ])roperly diluted 
is a desirable insecticide. 

Arsenate of Lead. Arsenate of lead, available in two forms 
— paste or as a white ])owder — may be secured on the market, 
or the arsenate may be formed by chemical combination of 
arsenic and lead. Formuliv for the use of this substance 
are as follows: 

Arsenate of load (p^ii^to) 3 to 10 pounds 

Water 50 gallons 

or 

Arsenate of lead (powder) 1 to 4 pounds 

Water 50 gallons 

For small quantities use: 

Arsenate of lead (paste) 1 teaspoonful 

Water 1 gallon 

If used as a spray this can be applied to a great variety of 
plants for the destruction of leaf-eatins: insects, and since 
it can be used at high strength without injury to foliage it 
may be used for the most resistant kind of insects. Its killing 
power is not equal to that of Paris green and consequently 
somewhat stronger solutions must be used. 

Like Paris green, it may be used in the (Iry fc^rm as dust 
or with a ])owder gun. 

Hellebore.- Hellebore is a white powder destructive to 
insects but not poisonous to domestic animals or man, unless 



MEASURES FOIi INSECT CONTROL 'Ml 

in large; (los(;s. It may he usee] as a spray or in a dry form 
and is apj>lif;al)l(; to currant })ushes or other kinds of fruit, 
for saw-fly larvae and other leaf-feeding insects where it is 
undesirable to use arsenic. 

Arsenical Bran Mash. — This is used as a })ait for cut worms 
and otficr inscc-ts which endanger vegetation and which it is 
desirable to kill before the; vegetation has been attack(;d. 
Formula as follows: 

Bran 25 pounda 

Paris Krocn ^ pound 

Cheap molasses 1 quart 

Water, as needed to moisten. 

For small quantities use: 

Bran 1 quart 

Paris green 1 teaspoorjful 

Cheap molasses 1 tablespoonful 

Water, as needed to moisten. 

For grasshoppers the attractiveness of this bait is very 
much increased by the addition of lime juir-c or r^rangf; or 
lemon flavor. 

Contact Insecticides. — Insecticides of this group def)end 
upon immediate contact with the insects to be affected, 
different kinds of sprays, direct applications and the use of 
fumigants which are distributed to the insects to be reached. 

Lime-sulphur wash is the most important of the insecti- 
cides now in use against the scale insects, especially the 
San Jose scale. The commercial lime-sulphur preparations 
on the market generally may be secured at seed-stores 
or from dealers in nursery or orchard supplies and depended 
upon as containing the correct proportions and if used 
according to directions should give very certain results. 
These can be secured at reasonable prices and are often 
preferable to the solutions of home preparation. How- 
ever, directions for the preparation of the compound may be 
of service and two formula; will be given, one for the conrrcn- 
trated solution to be diluted when used and the other for 
immediate use. 



318 PRINCIPLES OF ECONOMIC ENTOMOLOGY 




Fig. 250. — Making lime-sulphur solution ( i'hoto. Ohio K\\>. St;i.j 




Fig. 251. — Plant for making lime-sulphur solution in large quantities. 
(Photo. Ohio Exp. Sta.) 

Concentrated Lime-sulphur. 

Lump lime 50 pounds 

Sulphur 100 pounds 

Water (hot) 70 gallons 

Dilute as directed. 



MEASURES FOR INSECT CONTROL 319 

For exact preparation the use of the hydrometer is desir- 
able and the following scale of proportions is recommended. 

Reading on hydrometer Number of gallons of water to 1 gallon 

in degrees (Baum6). of the concentrated lime-sulphur. 

35 9 

34 8f 

33 8i 

32 8 

31 7h 

30 7i . 

29 6f 

28 , Qh 

27 

26 5| 

25 5i 

24 5 

23 4^ 

22 ' 4i 

21 3| 

20 3| 

19 3i 

18 3 

17 2f 

16 2h 

15 2i 

14 2 

Regular Lime-sulphur Wash (for winter spray). 

Lump lime 20 pounds 

Sulphur 12 pounds 

Water 50 gallons 

Kerosene. — The use of kerosene or petroleum combinations 
has given some of the most useful combinations and they 
still have a wide range of usefulness, although at present 
less used than the lime-sulphur solutions for scale insects. 
Generally they may be applied to practically all kinds of 
insects which are suctorial in habit and cannot be reached 
by arsenical sprays, but they are especially efficient against 
the scale insects at time of migration and against such soft- 
bodied insects as the plant lice. In the preparation of the 
kerosene emulsion it is extremely important that a thorough 
emulsion be obtained so there will be no separation of oil 
from the water, as there is much damage to the foliage if 
this occurs. 



320 PRINCIPLES OF ECONOMIC ENTOMOLOGY 

The standard formula for kerosene emulsion is as follows: 

Hard soap h pound 

Hot water (soft) 1 gallon 

Kerosene (coal oil) 2 gallons 

To form the emulsion take a gallon of soft water and 
dissolve in it a half-pound of soap, then remove from fire, 
add two gallons of kerosene, which should be thoroughly 
mixed and agitated at once. One of the best methods is to 
run the solution through a spray pump, driving it back into 
the bucket from which the solution is drawn, and about 
five or six minutes of this mixing will produce a perfect emul- 
sion. It should be carried to such completion that there 
will be no tendency for the oil to separate. Small quantities 
may be made rapidly in the proper proportions by the use of 
an egg-beater or by a process which produces a violent 
agitation which may be maintained for some length of time. 
This strong enjulsion should be kept in a cool place and 
covered or in a tight receptacle and may be diluted as wanted 
with soft water, the amount of dilution depending upon the 
insects to be reached. For scale insects, one pint of strong 
emulsion to nine parts water. Soft plant lice are readily 
killed by a solution of one part of stock solution to fifteen 
parts of water. 

Tobacco Extract. — This is a very efficient contact insecti- 
cide and may be used against many kinds of insects but 
especially such forms as plant lice, thrips, and the better- 
protected sucking insects. Various solutions are on the 
market but the one termed Black Leaf 40, containing 40 
per cent, nicotine sulphate, is one which seems to have 
proved one of the best; this is used in dilutions of 1 part 
to 300 of water to 1 part to 600 parts of water — for use in 
winter time, when plants are dormant, and for summer use, 
dilutions — 1 to 500, to 1 to 1000 are recommended for tender 
insects such as plant lice. Similar solutions may be used for 
parasitic lice and mites on domestic animals. 

Tobacco dust may be used or an extract prepared from 
this by steeping or soaking in w^ater overnight. In making 
the preparation boil one pound of dust or stems to a gallon 



MEASURES FOR INSECT CONTROL 321 

of water, and this may be diluted, one to two parts of water 
and applied for leaf-sucking insects. 

Pyrethrum or Persian Insect Powder. — This is a very power- 
ful insecticide when properly prepared, but loses its strength 
when exposed to air, so that particular care should be taken 
to keep it in a tightly closed receptacle or it must be used 
when quite fresh. It is a powdered material derived from the 
grinding of the leaves or flowers and buds of the Pyrethrum 
plant, the main supply coming from Dalmatia, but a consider- 





1 


1 


1 


1 


^PpliRly^ ^H' ' JB'^* 


Bl 


B^n^ 




^^^ 


i^iMi 


■■I 


k " 


■> ;--g^,*i, 





Fig. 252. — An orchard demonstration in spraying. 
(Photo. Ohio Exp. Sta.) 

able amount being produced in California. It is a volatile 
oil and it is the vaporization and contact of this which is 
destructive to the insect. It may be used as a spray by the 
dilution of one ounce of powder to two gallons of water, and 
is available for saw-fly larvae and other pests upon currants, 
gooseberries, etc., being especially valuable on account of 
its not being poisonous to man or domestic animals. The 
powder, blown into rooms is effective for the killing of 
mosquitoes and flies, but for this purpose does not compete 
21 



322 PRINCIPLES OF ECONOMIC ENTOMOLOGY 

with some other measures. It may be used upon dogs and 
eats for the kilHng of fleas by dusting in the hair. 

Machinery. — For the application of these various insecti- 
cides, a great many forms of spraying outfits, chisting 
machines, etc., have been devised. These are now so thor- 
oughly standardized and handled by reputable firms that 
anyone may secure such outfits as may be needed for his 
individual purpose. 

Cultural Methods. — ^Another distinct group of measures 
for insect control (the indirect methods) may include those 
which have to do with methods of culture and alternation of 
crops and various cultural methods which incidentally have 
an effect upon the activities of insects. 

First among these may be mentioned the general practice 
of crop rotation which for a good many insects serves in an 
admirable way to prevent undue multiplication of injurious 
forms. Aside from its advantages in other ways, rotation 
serves to dislodge or starve out a great number of insects 
which are not able to migrate readily and which become 
established in any field only after several years of uninter- 
rupted development. For such forms the plowing up of the 
fields or a change from one crop to another may prove an 
almost perfect control. A striking example of this has been 
noted in the case of the corn-root worm. In somewhat les- 
ser degree the process is available for many of the pasture 
and meadow insects which are dependent upon grasses as 
their main food supply and which when grass is plowed 
under, especially if this is done at a time when the insects 
are in larval or in a known migratory stage, serves to destroy 
them very efi^ectively. 

In a general way plowing will cut off the food supply, some- 
times will bury the insects to such a depth that they do not 
extricate themselves. In this connection, however, it is some- 
times very important that the condition of the insects be 
known, as there are cases, such as white grubs, sod worms, 
and wire worms, which if plowed under with the sod will, 
if a second crop is planted soon, transfer their attack to the 
new crop with very disastrous consequences. It frequently 



MEASURES FOR INSECT CONTROL 323 

happens that com planted on sod land is in this way very 
seriously injured. The precaution should be to plow under 
long enough before the new crop is planted to allow oppor- 
tunity for the starving out of insects which may be present 
in the grass. 

Another practise in this line is for such an arrangement of 
crops that insects which naturally migrate from one crop to 
another will be separated by a crop of different character, 
something that will not serve them as a food supply. For 
instance, the migration of the chinch bug from wheat fields 
into corn fields may be prevented by the introduction of a 
strip planted to potatoes, beans or some crop which is not 
available as chinch bug food. 

The use of an early planted crop for the purpose of attract- 
ing insect egg deposition with the view of destroying the 
insects so attracted and thus protecting the later crop, has 
been in vogue for many years and is applicable to such 
species as have several generations in a season. A good 
example of this is the corn-ear worm which if attracted to 
a small area of early planted corn which is fed to hogs at the 
time the worms begin work will assist much in the preven- 
tion of attacks on adjacent fields. 

In some cases where an insect is especially destructive in 
a certain area, resort may be had to the suppression of the 
cultivation of a crop for one or two seasons, thus eliminating 
food. This will largely diminish if not practically extermi- 
nate such insects as are strictly dependent upon this crop for 
existence. Naturally such a method is limited in application, 
as the complete suppression of any crop in a certain district 
is a difficult matter to accomplish. 

Clean culture is often recommended as an important 
aid in the suppression of insects, and there is no doubt that 
for many species attention to the elimination of food plants 
which assist them to survive and the cleaning up of litter 
in which they may hibernate will accomplish a great deal 
in the reduction of numbers and the consequent extent of 
injury. Clean culture, however, must be taken in connec- 
tion with a study of the habits of the species which it is 



324 PRINCIPLES OF ECONOMIC ENTOMOLOGY 

desired to control and cannot be considered as an efficient 
l^ractise for many insects that are troublesome on the 
avera<]:e farm. Tn this coimection it may be stated that it 
is good entomological j)ractise to use wire fences in place 
of the old rail or board fences, and it is a good plan to culti- 
vate as close as possible to fence lines with the consequent 
reduction of the growth of weeds, bushes, and so on. 

Another matter which deserves attention is a close guard- 
ing against the introduction of pests in seed or along with 
introduced ])lants, as many of the serious pests are readily 
transferred from place to place in such materials as straw 
and various kinds of seed packages and thus gain a foot- 
hold in a locality in which they have not been troublesome 
before. 

NATURAL ENEMIES. 

Insects are preyed upon by many natural enemies — birds, 
reptiles, toads, spiders, and these serve as checks to their 
inordinate increase. Bird protection has been strongly 
urged as an aid in insect control and certainly all or nearly 
all of our common field birds are best allowed all the pro- 
tection possible. Especially the small insectivorous birds 
such as wrens, swallows, chickadees, titmice, etc., should be 
given all the protection possible. Spiders are also generally 
useful rather than injurious and should be undisturbed. 

PREDACEOUS AND PARASITIC INSECTS. 

The position of the predaceous and parasitic insects is one 
of considerable complexity, since their attacks may be 
directed against both injurious and beneficial forms, and 
their relation to human interests depends, of course, upon 
the nature of the insects which they attack. In a general 
way the carnivorous species feed upon the herbivorous ones, 
and the herbivorous ones being ordinarily the most destruc- 
tive to valuable crops, the average result may be looked 
upon as advantageous. The study of these natural enemies 
of the injurious insects has formed a considerable part of 



PREDACEOUS AND PARASITIC INSECTS 325 

economic entomology, and the importance of the subject 
has been pretty generally recognized, though different 
workers have assigned quite different value or importance to 
to the subject. 

Predaceous insects are those which attack and devour 
other insects, possibly quite different kinds of insects, and 
do it without sacrificing their own activity or independence. 
Parasitic insects, using this term as it applies more particu- 
larly to economic entomology, are those which are dependent 
for a larger or smaller part of their existence upon some 
particular kind of insect host. Nearly all are internal 
parasites and in a great majority of cases the entire develop- 
ment of the individual from the egg to pupa or adult stage 
is passed within the body of a single individual host. Some- 
times a large number of individuals will develop within a 
single host, as in case of the minute ichneumons which 
parasitize the larger caterpillars. 

It must be noted here that a parasite itself may be para- 
sitized by another species called a "secondary" parasite 
which, by reducing the numbers of the parasitic species, 
would become from the economic stand-point injurious. 
This, again, in some instances may support still another 
parasite, a so-called "tertiary" parasite, which by reducing 
the numbers of the secondary parasite would be detrimental, 
and a fourth, where such occurs, again assumes the opposite 
role. It is evident where such a complex condition of para- 
sites exists that it is practically impossible to adopt any 
means of encouraging the beneficial or destroying the inju- 
rious ones, and that this complex system of wheels within 
wheels must be allowed to work out its own conclusion in the 
balance of nature. 

For most species there is perhaps but little that can be 
done in the way of preserving the beneficial parasites or of 
facilitating their work. We simply allow them to go on un- 
molested, serving so far as they may, as a natural check upon 
the injurious species. Many of our destructive insects are 
insects that without this check would be seriously destruc- 
tive, the regular attacks of these parasites serving very 



326 PRINCIPLES OF ECONOMIC ENTOMOLOGY 

efi'ectively to keep the destructive species in reasonable 
bounds and often preventing it from causing any serious 
loss. The Hessian fly is certainly kept in check during a 
considerable portion of the time by just such agencies, and 
we can scarcely doubt that if the parasites of this species 
were eliminated and other conditions unaffected, the losses 
incurred would be enormously increased. 

With some species it may be possible to assist the para- 
sitic forms or to preserve them in such manner as to get the 
advantage of their service. For instance, the cabbage 
butterfly is very commonly parasitized by a small ichneu- 
monid {Pteromalus) which issues from the pupae, and it is 
evident that if the pupae were gathered and instead of being 
crushed were enclosed in wire screen of such mesh as to 
retain the issuing butterflies but allow the free escape of 
the minute parasites, there would be a destruction of the 
healthy butterflies without any reduction in the numbers of 
the parasites. Again, in the case of the Hessian fly, care, 
as to the time when the stubble is burned or plowed under 
in order to allow opportunity for escape and survival of 
the parasites, might be of special service in their protection. 
In California extensive shipments of lady bugs from the 
northern part of the State to the Imperial valley to prey 
upon the plant lice affecting melons is claimed to have 
accomplished much in their control. 

On the whole, however, the utilization of parasites in a 
direct manner can hardly be depended upon as a very great 
advantage, especially because of the difficulty in so training 
the average cultivator that he will be able to distinguish 
between parasites and non-parasitic forms, and adapt his 
practice to accommodate them. 

A more important phase of the subject perhaps is found 
in the transportation of parasitic species from one country 
to another where an injurious species has been introduced 
without the introduction of its native enemy. It has already 
been suggested that the original habitat of an injurious 
insect is a matter of great importance, especially with 
reference to its natural parasites, and a number of instances 



EXCLUSION AND RESTRICTION 327 

are now in evidence showing the possibility of controlling 
injurious, introduced species by means of the introduction of 
the native enemies. The most conspicuous is that of the 
cottony cushion scale, introduced into California several 
years ago, and in more recent years the very extensive intro- 
duction of predaceous and parasitic enemies of the Gipsy 
and brown-tail moths in the New England States for the 
control of these very destructive imported pests. 

EXCLUSION AND RESTRICTION. 

These are most important means of controlling insect 
depredations. Formerly the entomologist devoted his 
entire attention and effort to the study of native species 
but now his attention is largely directed toward exclusion 
from and restriction in the United States of new insects. 
Until recently in the introduction of new plants from foreign 
countries, no attention has been paid to the new insects 
introduced with them. An important part of the work of 
the entomologist in the future will be to study the insects 
of other countries— not only those that are now destructive 
there but those that do no particular damage, yet when 
the natural checks are removed, are likely to become 
destructive. 

Special attention must be paid to those insects which are 
native in those countries from which we import a greater 
part of our plants. Some of the foundation principles in the 
study are : 

1. An insect, coming from another country, is more likely 
to become destructive here if it comes from a somewhat 
similar climate, and if the food plants are somewhat closely 
related to those of its native country. 

2. Insects coming from different climates may, if they have 
a wide range of food plants, adapt themselves to the new 
climate. It will then be proper to consider tropical species, 
especially if their food plants are widely distributed and 
have nearly related species in the country to which they are 
brought. 



328 PRINCIPLES OF ECONOMIC ENTOMOLOGY 

3. Tropical insects that arc limited to tr()})ical ])laiits for 
food, will have little importance in temperate regions excej)t 
in greenhouses. 

Most of the scale insects are tropical and in this climate 
are on the borderline of their destructive region, hut on 
account of their general food habits the\' constitute a general 
pest. 

The question of the control of the distribution of the 
destructive species is yet a new problem and one over which 
there is considerable dispute; any measure intended to exclude 
a foreign species must be adapted to a particular species, as 
a general law will not suffice. Even the general exclusion of 
the food plant will not alone be effective in keeping out the 
pest, as it may have other means of dispersal. 

Inspection and enforcement of restrictions at the port of 
entry are being quite generally adopted. Inspection is most 
effective when applied to plants. Sometimes it is necessary to 
introduce a foreign species to prey on another foreign insect 
that is already here, as was the case with cottony cushion 
scale in California. 



GLOSSARY OF THE TERMS USED IN 
ENTOMOLOGY. 

Abdomen. The posterior region of the insect body. 

Abiogenesis. Spontaneous generation. 

Abraded, Scraped or rubbed. 

AcALYPTRATA. Thosc muscid flies in which alulse are absent or 
rudimentary. 

Aculeate. Prickly; armed with a sting. 

Acuminate. Tapering to a long point. 

Addorsal. Close to but not on the middle of the dorsum. 

Adephagous. Belonging to the Adephaga; pentamerous, predatory, 
terrestrial beetles with filiform antennae. 

Adpressed. Contiguous or pressed to. 

Agamic. Reproducing without union with a male. 

Agamogenesis. Reproduction without fertiUzation by a male; 
parthenogenesis. 

Agglutinate. Glued together in a mass. 

Aggregated. Crowded together. 

Ala (pi. Al^). Wing or wings. 

Alary. Relating to wings. 

Alate. Winged. 

Alternation of Generations. Periodic production of partheno- 
genetic females in a species that occurs in both sexes. These females 
produce both sexes. Examples occur in Cynipidae and in some 
Homoptera. 

Alul^. a pair of membranous scales above the halteres, behind the 
root of the wing, one above or before the other; the anterior attached 
to the wing and moving with it, the posterior fastened to the thorax 
and stationary. Occurs in Diptera. Synonyms calyptra; squama; 
squamula; lobulus; axillary lobe; aileron; scale; tegulse. In Cole- 
optera, a membranous appendage of the elytra which prevents 
dislocation. 

Alulet. The lobe at basal portion of wing in Diptera. 

Ametabola. Insects not having obvious metamorphosis, the larvse 
resembling the adult and the pupae being active. 

Amnion. The inner of the two membranes enclosing the embryo. 

Amphimixis. The mingling of the germ plasm of two individuals. 

Ampulla. In Orthoptera, an extensile sac between the head and 
prothorax, used by the young in escaping from the ootheca, and later 
in moulting. In Heteroptera, a blister-like enlargement at the middle 
of the anterior margin of the prothorax. 

Anal. Pertaining or attached to the last segment of the abdomen. 

Anal angle. That angle on the secondaries nearest the end of the 
abdomen when the wings are expanded. The angle between the inner 
and outer margin of any wing. 

(329) 



330 GLOSSARY OF TERMS USED IN ENTOMOLOGY 

Anal appendages. The external genital parts. 

Anal area. In Orthoptcra and Neuroptera, the hinder or anal 
portion of a wing within the anal vein. 

Anal field. That area on the tegmina of Orthoptera corresponding 
to the anal area of the secondaries. 

Anal plate. In caterpillars, the shield-like covering of the dorsum 
of the last segment. 

Annulate. Marked with colored rings or bands. 

Annulus. a ring. 

Ante -APICAL. Before or in front of the apex. 

Antennae. Two-jointed organs of sensation situated on the head. 

Antepectus. The lower surface of the prothorax. 

Antigeny. Sexual diversity. 

Anus. The posterior opening of the digestive tract. 

Apex. The terminal portion of any organ of body, the part farthest 
away from the base. 

Appendiculate. Bearing appendages. 

Appendix. A part added or attached to another part. 

Apterous. Without wings. 

Aquatic. Living in the water. 

Araneiform. Spider-like in appearance. 

Arboreal. Living in or on trees. 

Arborescent. Branching. 

Arcuate. Bowed or curved. 

Arenose. Sandy, not smooth. 

Areola. A small cell on the wings of certain Hemiptera. 

Arista. A specialized bristle or process on the antenna of certain 
Diptera. 

Arolium. Cushion-like pads on the tarsi of many insects. 

Arthropoda, Jointed animals having jointed appendages. 

Articulate. Divided into distinct joints. 

Articulation. Joint; place where two joints meet. 

Asexual. Without sex. Reproduction which does not involve the 
union of individuals of different sexes. Reproduction by budding, etc. 

Ater. Deep black, 

Atomarius. With minute points or dots. 

Bifid. Split, two parts. 

Bifurcate. Divided; forked. 

Bionomics. The habits, breeding, and adaptations of living forms. 

BisERRATE. Saw^-toothed on two edges. 

BiviTTATE. Having two longitudinal stripes. 

Brachycerous. Having short three-jointed antennae, Diptera. 

Brachypterous. Short- winged. 

Bristle. A short, stiff hair. 

Buccal. Relating to the mouth cavity. 

Bulla. A blister or blister-like structure. 

CiECUM, A blind sac or tube opening into the alimentary canal. 
Calypter. In Diptera, the alula when it covers the haltere. 
Campodeiform. Resembling campodea. 

Canaliculate. Grooved longitudinally, with a concave line in the 
middle. 



GLOSSARY OF TERMS USED IN ENTOMOLOGY 331 

Cancellate. Cross-barred; latticed. 

Capillary. Hair-like; long and slender. 

Capitate. Terminating in a little head or knob. 

Caprification. Process of fertilization of Smyrna figs by Blasto- 
phaga through the medium of "caprifigs." 

Carabidoid. Resembling a Carabid. 

Carina. An elevated ridge. 

Carnivorous. Flesh-eating. 

Cauda. The tail; any process resembling a tail. 

Caudad. Toward the posterior region of the body. 

Caudal. Pertaining to the posterior end of the body. 

Caudal set^. Thread-like processes at the end of the abdomen. 

Caudate. Having tail-like extensions. 

Caverniculous. Cave-inhabiting. 

Cell. Space within the veins on the wing. 

Cellule. A small space included between the veins on the wing. 

Cephalad. Toward the head. 

Cephalic. Belonging to the head. 

Cervical. Relating to the neck. 

Chaetotaxy. The science dealing with the arrangement and 
nomenclature of the bristles on the body of insects. 

Chelate. Having a claw. 

Chitin. The material of which the hard parts of the insect body are 
formed. 

Chitinous. Composed of chitin or similar to chitin. 

Chrysalis — id. The intermediate stage between larva and adult; 
see pupa. 

Cicatrix. A scar; an elevated, rigid spot. 

Cilia. Fringes. 

CiLiATE. Fringed; set with parallel hairs or bristles. 

Clasper. a chitinized process, free or attached to the inner sides 
of valves or other lateral pieces and serving to hold the female parts 
during' copulation; the harpes. 

Claval suture. Indentation separating the clavus at the base of 
the hemelytra in Hemiptera. 

Clavate. Club-shaped; thickening gradually toward end. 

Clypeus. The anterior median portion of the head to which the 
labrum is usually attached. 

CoARCTATE. Contracted; compact. 

Cocoon. Silky covering enclosing pupa. 

CoLLUM. The neck or collar. 

Colon. The large intestine. 

Connate. United at base, or along the whole length. 

CoNNEXivuM. The prominent abdominal margin of Heteroptera at 
junction of dorsal and ventral plates. 

CoPROPHAGUS. Feeding on excrement on or decaying vegetable 
matter of an excrementitious character. 

Cordate. Heart-shaped. 

Coriaceous. Leather-like. 

CoRiuM. The elongate middle section of the hemelytra which 
extends from base to membrane below the embolium. 

Cornicles. The honey-tubes in plant lice. 



332 GLOSSARY OF TERMS USED IN ENTOMOLOGY 

Costa. An elevated ridge that is rounded at its crest; the thickened 
anterior margin of a wing. 

Costal area. The area behind the costal vein. 

Costal cell. The area inclosed between the costal antl subcostal 
veins. 

Coxa. The basal segment of the leg. 

CoxAL cavity. The opening or space in which the coxa articulates. 

Crenate. Scalloped. 

Crepuscular. Active at dusk. 

Cristate. Crested. 

Dentate. Toothed. 

Dentate-serrate. Tooth-serrated: the denticulations themselves 
being serrated on their edges. 

Dichoptic. Eyes separated by front, not contiguous. 

DicHOTOMOUs. Forked, dividing by pairs. 

Dimorphic. Occurring in two well-marked forms. 

Dimorphism. A difference in form, color, etc., between individuals 
of the same species, characterizing two distinct types. 

Dioecious. Having distinct sexes. 

DiscAL. On or relating to the disk of any surface or structure. 

DiSTAD. Toward the distal end. 

Distal. That part of a joint farthest from the body. 

Divergent. Spreading out from a common base. 

Dominant. A character more constant and conspicuous than any 
other. 

Dorsad. Toward the upper surface. 

Dorsal. Of the back. 

Dorsum. The upper surface. 

Drone. The male bee in Hymenoptera. 

Ecaudate. Without tails or tail-like processes. 

EcDYSis. Moulting or casting of the skin. 

Ecology. The science of the relation of organisms to each other 
and to their surroundings. 

EcTAD. Extending outwardly from within. 

EcTAL. Relating to the outer surface. 

Elytra. The anterior leathery or chitinous wings of beetles. 

Embolium. The narrow sclerite extending along the anterior margin 
of the hemelytra, from base to cuneus or membrane, in Heteroptera. 

Empodium. The small process between the pul villi in Diptera. 
The bifid pseudotarsi between the claws in Coleoptera. 

Ensiform. Sword-shaped. 

Entad. Extending inwardly. 

Ental. Pertaining to the centre of the body cavity. 

Entire. With an even, unbroken margin. 

Entomogenous. Growing in or on an insect. 

Entomophagous. Insect-feeding. 

Episternum. The anterior and larger lateral thoracic sclerite 
between the sternum and notum. 

Epizoa. Insects that infest the body surface of animals. 

Ergatoid. Wingless ants, sexually developed. 



GLOSSARY OF TERMS USED IN ENTOMOLOGY 333 

Eruciform. Caterpillar-like in appearance. 

Exotic. An introduced species, not native to the place found. 

ExsERTED. Protruded. 

Facet. One of the small divisions of the compound eye. 
Fasciate. Banded. 

Femur (pi. femora). The thigh between the coxa and tibia. 
Filiform. Thread-like. 

Flabellate. With long, flat processes folding like a fan. 
Formic. Pertaining to or derived from ants. 
Formicary. An ant's nest or ant hill. 

Front. Anterior portion of the head between the base of antennae 
and below the ocelli. 
Fumose. Smoky. 

FuNGicoLOUS. Living in or on fungi, 
FuRCA. A fork or forked process. 
Furcate, Forked. 
Fuscous. Very dark brown. 

Gena. Cheek; that portion of the head below the eyes on each side 
extending to the gular suture. 
Generation. Brood. 

Genitalia. External organs of reproduction and their appendages. 
Granulated. Covered with small grains. 
Gregarious. Living in groups or communities. 
Griseus. Light gray. 
Guttate. Spotted, light spots on dark ground. 

Habitat. The locality in which an insect lives. 

Haustellate. Formed for sucking. 

Haustellum. Sucker; the part of the mouth through which liquids 
are sucked. 

Hermaphrodite. A bisexual individual. 

Heterogamy. Alternation of generations, two sexual or a sexual 
and a parthenogenetic. 

Hibernaculum. a tent or sheath in which a larva hibernates. 

Hibernate, To pass the winter in a dormant condition. 

Hypermetamorphosis. The case in which an insect passes through 
more than the normal stages of development. 

Hyperparasite. a parasite that is parasitic upon another parasite. 

Imaginal Pertaining to the adult or imago. 
Imago, The adult or sexually mature insect. 
Infumated. Clouded. 

Infuscated. Smoky gray-brown, with a blackish tinge. 
Inquiline. a species living in a gall made by another species, not 
as a parasite but as a guest. 

Inquilinous. Living as guests in the homes of others, 
Insectary, a place where insects are bred for the purpose of study , 
Instar. The period or stage between moults in the larva. 
Integument. The outer covering to the insect body. 
Intima. The lining membrane of the trachea. 



334 GLOSSARY OF TERMS USED IN ENTOMOLOGY 

Invaginate. When a tubular or vesicular part is turned inward or 
retracted within the body wall. 

Iridescent. Reflecting the prismatic colors. 

Iris. The circle which, in an ocellate spot surrounds the pupil. ^ 

Irrorate. Marked with fine points. 

Iso. Equal. 

Juga. The lateral anterior lobes of a Heteropteron ; each side of 
the tylus. 

Labellum. The sensitive ridge tip of the mouth structures of 
certain Diptera; a prolongation of the base of the rostrum in Coleoptera 
and Hemiptera. 

Labial. Pertaining to the labium. 

Labium. The lower lip. 

Labrum. The upper lip. 

Lacinia. The inner lobe of the first maxilla, articulated to the stipes, 
bearing brushes of hairs or spines. 

Lacuna. Irregular cavities. 

Lamella. A thin plate. 

Lamellate. Divided laterally into distinct leaf -like plates. 

Lanceolate. Spear-shaped. 

Larva. The second stage in the development of the insect, follows 
immediately after the egg stage. 

Larvarium. The shelter-case of the larva. 

Laterad. Toward the side and away from the median line. 

Lateral. On the side. 

Littoral. Living along the seacoast or in the shore debris. 

LoRA. The chitinous bands connecting the submentum with the 
cardo of the maxilla. 

Lumen. The cavity or hollow part of an organ or tube. 

Lunula. A small crescent-shaped mark. 

LuNULE. A lunate mark or crescent. 

Macroch.et.^. The long bristles occurring singly on the body of 
Diptera. 

Macropterous. Long or large winged. 

Macula. A colored mark larger than a spot and of no definite shape. 

Maggot. The footless larva of Diptera. 

Mammilate. With nipple-like protuberances. 

Mandible. The lateral upper jaws of a biting insect. 

Mandibulate. Having jaws or mandibles. 

Maxilla. Jaws; one on each side of the mouth immediately 
beneath the mandibles. 

Maxillary. Belonging to the maxilla. 

Meconium. The substance excreted by certain metabolic insects 
soon after their emergence from the chrysalis. 

Mediad. Toward the middle. 

Medial. Referring to or at the middle. 

Median. Middle. 

Melanic. Blackish. 



GLOSSARY OF TERMS USED IN ENTOMOLOGY 335 

Melanism. An abnormal darkening. 

Mellifera. Honey-makers. 

Mentum. a labial sclerite bearing the movable parts. 

Mesenteron. The middle portion of the primitive intestinal canal ; 
the midgut. 

Meso-. Middle. 

Mesonotum. The primitively upper surface of the middle thoracic 
ring. 

Meta-. Posterior. 

Metabolism. Transformation, changes of food into tissue and of 
tissue into waste products. 

Metanotum. The primitively upper surface of the third or posterior 
thoracic ring. 

Metathorax. The third thoracic ring or segment. 

Metopidium. The anterior declivous surface of prothorax in Mem- 
bracidse. 

Microch^t^. Small bristles, as opposed to macrocha^tae, in Diptera. 

Micron. The unit of microscopic measurement. 

Mimetic. Mimicry of appearance but not structure. 

Mimicry. The resemblance of one animal to another not closely 
related. 

Monoecious. The combining of both sexual elements in one indi- 
vidual. 

Moult. The transformation of a larva from one instar to another; 
the cast skin of a larva that has moulted. 

Ne arctic. Temperate and arctic North America, including Green- 
land. 

Necrophagous. Living in or on carrion. 

Nectaries. Honey-tubes. 

Neotropical. That part of the earth's surface embraced in the 
greater part of Mexico, West Indies and South America. 

Nocturnal. Night-flying. 

Obsolete. Indistinct, nearly or entirely lost. 

Obtect. Wrapped in a hard covering. 

Obtected. Covered with a chitinous case which conceals appendages 
but through which their outlines are revealed. 

Ocelli. Plural of ocellus. 

Ocellus. A simple eye. 

Ontogeny. The development of the individual as distinguished from 
that of the species. 

Ootheca. The covering of an egg mass. 

Operculum. A lid. 

Optic. Relating to the organs of vision. 

Oral. Pertaining to the mouth. 

Oriental. In geographical zoology as used by Wallace, that part of 
the earth's surface including Asia east of the Indus River, south of the 
Himalayas and the Yangtse-kiang watershed, Ceylon, Sumatra, Java, 
and the Philippines. 

Ova. Eggs. 



336 GLOSSARY OF TERMS USED IN ENTOMOLOGY 

Ovum. An egg. 

OviPosiTiON. The act of depositing the eggs. 

Ovipositor. The structure by means of which the eggs are placed. 

P.EDOGENESis. Reproduction in the hirval stage. 

Palearctic. Relating to that part of the earth's surface including 
Europe, Africa north of Sahara, and Asia as far as the southern edge of 
the Yangtse-kiang watershed and the Himalayas, and west to the Indus 
River. 

Pallid. Pale. 

Palmate. Like the palm of the hand with finger-like processes. 

Palpus. Articulated moveable appendage in the mouth of insects. 

Parasitic. Living on or in another animal or insect and dependent 
on the host for food and support. 

Parthenogenesis. Reproduction by direct growth of germs from 
egg-cells without fertilization by the male. 

Parthenogenetic. See asexual. 

Pectus. The ventral portion of the thorax. 

Pelagic. Living in the open sea. 

Pellucid, Colored, but transparent; sometimes no color. 

Petiolate. Placed on a stalk. 

Phylogeny. The developmental relationship of a genus, family, or 
other group. 

Pile, A fur-like covering. 

PiLiFERous. Having a covering of pile. 

Plicate. Folded like a fan, plaited. 

Plumose. Feathered, like a plume. 

Pollinose. Covered with a pollen-like dust. 

Polyandry. Mating of one female with more than one male. 

Polyembryony. Production of more than one embryo from one egg. 

Polygamy. Mating of one male with more than one female. 

Posterior. Hinder or hindermost; opposed to anterior. 

Predaceous. Living upon other organisms. 

Predatory, Predaceous. 

Primaries. The anterior or fore-wings. 

Primitive. Simple in character; of an early or ancient type. 

Pro-. Anterior to. 

Proboscis. The extended mouth structure. 

Proximad. Toward the proximal end. 

Proximal. That part of an appendage nearest the body. 

Pruinose. Hoary, covered with fine dust, / 

Pseud imago. Subimago. 

Pseud- or pseudo-. Prefix meaning false. 

Pseudogyne. a female that reproduces without impregnation. 

Pseudova. Egg-like germ cells capable of development without 
fertilization. 

Pulverulent. Powdery. 

Pupa. The intermediate stage between larva and adult. 

PuPARiUM, The thickened larval skin within w^hich the pupa is 
formed. 

Pupate. To become a pupa. 

Pupation. Becoming a pupa. 



GLOSSARY OF TERMS USED IN ENTOMOLOGY 337 

Pygidium. The last dorsal segment left exposed by the elytra. 
Pygofer. The last segment of the abdomen in certain Homoptera, 
especially the lateral margins which appear in ventral view. 

Radial. Pertaining to the radius or radial vein. 
Rostrum. A snout-hke prolongation of the head. 

ScABER. Rough, uneven. 

Scape. The second articulation of the antenna?, often elongated. 

Scutum. The second dorsal sclerite of the meso- and metathorax. 

Sensoria. The circular openings covered by membrane on the 
antennae or legs of plant lice. 

Serrate. Like the teeth of a common saw. 

Sessile. Closely attached. 

Setaceous. Bristle-shaped, slender, tapering. 

Social. Living in communities. 

Spermatogenesis. Development of the spermatozoa. 

Spinneret. Any organ consisting of an internal tube, terminating 
in a pore, spine or process, producing a silky or waxy fiber. 

Spiracle. A breathing pore opening to the trachea. 

Stage. A period in the course of development. 

Stellate. Star-shaped. 

Sterile. Incapable of reproduction. 

Sternite. The ventral piece in a ring or segment. 

Subimago. The stage in ephemerids and some other insects just 
after emergence from the pupa and before the final moult during flight. 

Tenent hair. Specialized hair adapted for clinging or clasping. 

Teneral. That state of the imago just after its exclusion from pupa 
or nymph, in which neither coloring nor clothing is fully developed. 

Teres, terete. Cylindrical. 

Tergal. Belonging to the primitively upper surface. 

Thorax. The second or middle portion of the insect body, bearing 
the true legs and wings; made up of three sections, the pro-, meso- 
and metathorax. 

Trachea—^. The breathing tubes of insects. 

Tracheate. Supplied with a trachea. 

Tracheoles. The capillary trachea of the adult as they develop 
in masses in the larva; very small, slender trachese. 

Transition zone. The transcontinental belt in which the austral 
and boreal elements overlap; it is divided into a humid or Alleghanian 
area, a western arid area, and a Pacific coast humid area. 

Trochantine. The basal part of the trochanter when it is two- 
jointed. 

Tumid. Swollen. 

Tylus. The anterior central lobe of the head in Hemiptera. 

Unicolorous. Of one color throughout. 

Vaginate. Inclosed in a bivalved sheath. 

Valve or Valvul.e. The expanded plate-like galea of the maxilla in 
many Hymenoptera. 
22 



338 GLOSSARY OF TERMS USED IN ENTOMOLOGY 

Valve. A small, transverse or triangular piece behind the last full 
ventral segment, at the base of plates in male Jassidic and allies. 

Venation. The system of chitinous framework supporting the wings. 

Venter. The inferior or under portion of the abdomen. 

Vestigial. Undeveloped or degenerate; the trace or remnant of a 
previously functional organ. 

Vestiture. The surface covering. 

Viscera. The internal organs of the body. 

Visceral. Pertaining to the viscera. 

Vitta. a longitudinal, colored line. 

Vittate. Striped. 

Viviparous. Bearing living young. 

Wing pads Undeveloped wings of pupa or nymph. 



INDEX. 



Abdomen of insects, structure, 42 

Acanthidse, 147 

Acarina, 25 

Acrididse, 59 

Adalia bipunctata, 177 

Adult stage of insects, 47 

Agallia sanguinolenta, 107 

Alabama argillacea, 227 

Aleyrodidae, 129 

AKalfa caterpillar, 243 

weevil, 195 
American silk worm, 240 
Ametobolic, 48 
Anasa tristis, 156 
Anatomy of grasshopper, 39 
Anopheles maculipennis, 249 

punctipennis, 249, 250 
Anosia plexippus, 245 
Antenna}, 38 

Anthonomus grandis, 198 
Ant lions, 169 
Ants, 305 

Apanteles glomeratus, 296, 297 
Aphaniptera, 50 
Aphanothrips striata, 90 
Aphidida?, 117 
Aphids, 117, 118 
Aphis maidis, 123 

maidi-radicis, 123 
Aphrophora 4-notata, 104 
Apidse, 310 

Appendages of insects, head, 38 
Apple aphis, 126 

leaf hopper, 115 

maggot, 287, 288 
Apterygota, 48 
Arachnida, 22 
Aradida), 314 



Araneida, 24 
Argas miniatus, 31 

persicus, 31 

reflexus, 30 
Argentine ant, 307, 309 
Armored scales, 134 
Army worm, 227 
Arphia sulphurea, 67 
Arsenate of lead, 316 
Arsenical bran mash, 317 
Arthropoda, 17 
Aspidiotus perniciosus, 137 
Assassin bugs, 145 
Athysanus exitiosus, 113 

obtutus, 106 
Atropos, work of, 82 

divinatoria, 83 
Auchenorhynchi, 94 



B 



Bag-w^orm moths, 207 
Balaninus obtusus, 198 

proboscideus, 196, 197 
Bark beetles, 203 

hce, 130 
Basilarchia archippus, 247 
Beach locust, 65 
Bed-bug, 147 
Bee moth, 213 
Bees, 310 

and wasps, 291 
Beetles, 172 

Belostoma americana, 144 
Belostomidse, 142 
Bembecidae, 310 
Bembecina?, 308 
Benacus griseus, 144 
Bird lice, 83 

(339) 



340 



INDEX 



Bird tick, 28 

Bittacus, 170 

Black flies, 2G0 

Blattida?, 55 

Blissus leucoptcrus, 151 

Blood-sucking cone nose, 145 

Blow flv, 277, 286 

Blue-bottle fly, 285 

Body structure, 38 

Boir weevil, 198 

worm, 226 
Book lice, 81 
Boreus, 170 
Bot flies, 267 
Box elder bug, 156 
Braconidiie, 296 
Bran mash, arsenical, 317 
Bristle tails, 48 
Brown-tailed moth, 233 
Bruchidte, 193 
Buffalo gnats, 260 

treehopper, 99 » 

Bumble bee, 310 
Buprestidse, 181 
Butterflies, 241 
Bythoscopidse, 107 



Cabbage butterfly, 242 
Cacsesia roseana, 215 
Caddice flies, 170 
Calosoma calidum, 173 

scrutator, 173, 174 

sycophant a, 174 
Camnula pellucida, 63 
Campodea, 48 
Canker worm, 225 
Capsidse, 150 
Carabidse, 173 
Carpet beetles, 179 

moth, 222 
Carpocapsa pomonella, 215 

saltitans, 218 
Carrion beetles, 174 
Cat flea, 290 
Cattle louse, biting, 85 

tick, 31 
Cecropia moth, 240 
Cerambycidse, 185 
Cercopida}, 104 



Ceresa bubalus, 90 
Ceuthophilus, 68 
Chalcidida), 296, 300 
Chalcis ovata, 300 
Chestnut weevil, 190 
Chiggers, 26 
Chilopoda, 17 
I Chinch bug, 151 
I Chionaspis furfurus, 136 
I salicis, 135, 136 
I Chion cinctus, 187, ISS 
1 Chironomidae, 253 
Chrysobothris femorata, ISl 
I Chrysomelida?, 190 
Chiysopa oculata, 167 
Chrysopidse, 165 
Cicada killer, 310 
Cicadidai, 94 
Cicadula 6-notata, 114 
Cicindelidae, 173 
Cimbex americana, 292 
Cimex lectularius, 147, 14S 
Circulatory system of insects, 43 
Classification of insects, 4S 
CUck beetles, 180 
Clisiocampa americana, 235 
Close wings, 214 
Clothes moth, 222 
Clothilla, 82 
Clover-flower midge, 254 

leafhopper, 107, 108 

-leaf weevil, 195 

-root borer, 205 

-seed caterpillar, 219 
Clypeus, 40 
Coccidse, 130 
, Coccinse, 132 
I Coccinellidse, 175 
! Cockroaches, bb 
Codling moth, 215 
Coleoptera, 50, 172 
CoHas philodice, 245 
Collembola, 48, 54 
! Colorado potato beetle, 190 
I Conocephalus, 67 
I Conorrhinus sanguisugus, 146 
Conotrachelus nenuphar, 196 
Contact insecticides, 317 
Control, insect, 315 
Copris Carolina, 183 
Coquillettia, 151 

mimetica, 149, 151 



INDEX 



341 



Coreidse, 155 
Corisa harrisii, 141 
Corisidse, 141 
Corizus, 158 

crassicornis, 158 
Corn delphacid, 103 

-leaf aphis, 123 

-root aphis, 123 

worm, 191 
Cornicles, 118 
Corrodentia, 49, 81 
CorydaUs cornuta, 165, 166 
Cossidse, 210 
Cotton boll weevil, 198 

worm, 227 
Crambidse, 214 
Crambus, 214 
Ctenocephalus canis, 290 
Cucujidse, 177 
Culex tseniorhynchus, 251 
Culicidae, 248 
Cultural methods, 322 
Cut worms, 229 
Cyclorhapha, 266 
Cynipidae, 295 
Cyrtophyllum concavum, 68 



Dactylopiin-e, 131 
Daddy-longlegs, 23 
Damsel flies, 74 
Danaidse, 245 

Dasyneura leguminicola, 254 
Datana, 224 

ministra, 224 
Delphacidse, 103 
Deltocephalus inimicus, 111, 112 
Dendroctonus, 205 

valens, 203, 204 
Dermacentor albipictus, 33 

venusta, 32, 33 
Dermanyssus avium, 28 

gallinse, 29 
Dermaptera, 49, 70 
Dermestes lardarius, 178 
Dermestidae, 178 
Destructive leaf hopper, 113 
Devastating locust, 60 
Diabrotica, 191 

longicornis, 191, 192 



Diabrotica 12-punctata, 192, 193 

vittata, 191 
Diapheromera femorata, 58 
Diaspinse, 134 
Dicranbtropis maidis, 103 
Digestive system of insects, 42 
Dineutes americana, 174 
Diplopoda, 18 
Diptera, 50, 248 
Direct methods for insect control, 

315 
j Dissosteira Carolina, 66 
Dog-day cicada, 98 

flea, 290 
Dorycephalus platyrhynchus, 110, 

111 
Draeculacephala mollipes, 109 
Dragon flies, 74 
Drosophila, 287 
Dytiscidae, 174 



E 



Earwigs, 49, 70 

Economic entomology, 17, 302, 313 
Ectobia germanica, 57 
Eggs of insects, 45 
Elateridae, 180 
Ehn-leaf beetle, 192 
Empoasca maU, 115 
Endelomyia rosse, 293 
Enemies, natural, of insects, 324 
Engraver beetles, 203 
Epeira scolopetaria, 24 
Ephemerida, 49, 72 
Ephestia kuehniella, 212 
Eriocampoides limacina, 293 
Euphorocera claripennis, 276 
Euplexoptera, 70 
Eurymus eurytheme, 243 
I Euthrips pyri, 89, 90 
Euvanessa antiopa, 247 
Exclusion and restriction method of 

insect control, 327 
Eyes of insects, 39 



Fall canker worm, 226 
Field ants, 307 



342 



INDEX 



Fire fly, 182 
Flat-headed borer, 181 
Fleas, 289 
Flesh flies, 286 
Food habits of insects, 314 
Forest flies, 288 
Formicidffi, 305 
Formicina, 305 
Fruit-tree bark beetle, 205 
Fiilgorida?, 101 



Galerucella luteola, 194 
Galleria mellonella, 213 
Gall gnats, 253 
Gamasidse, 28 
Gastrophilus equi, 267, 268 

ha^morrhoidalis, 270 

nasalis, 270 
Geometridse, 225 
Giant water bug, 142 
Gipsy moth, 232 
Glassy-winged sharpshooter, 109 
Glossary of terms, 329 
Glossina morsitans, 283 

palpalis, 283, 284 
Gnats, 253 

Grain aphis, spring, 123 
Grape leaf hopper, 114 

phylloxera, 129 
Grapholitha interstinctana, 219 
Grass thrips, 90 
Green-bottle fly, 286 

bug, 123 
Ground beetles, 173 
Gryllida?, 69 

Grvllotalpa Columbia, 70 
Gula, 40 
Gyrinidse, 174 
Gyropus, 84 



H 



Hackberry-gall psyllids, 116 
Hajmatobia serrata, 279 
Hsematopinus eurysternus, 161, 162 

urius, 162 
Handmaid moths, 224 
Harlequin cabbage bug, 159 
Harvestmen, 23 



I Harvest mites, 26 
i Hazel-nut weevil, 198 
\ Head of insects, structure, 38 
Heliophila unipuncta, 228 
j Hellebore, 316 
} Hemiptera, 49, 93 
Hesperidai, 241 
Hessian fly, 255 
Heterometabolic, 48 
Heteroptera, 93, 140 
Hexapoda, 38 
Hickory borer, 187 
Hippoboscida^, 288 
Hippodamia convergens, 176 
Hog louse, 162, 163 
Holometabolic, 48 
Homalomyia brevis, 287 
Homoptera, 93 
Honey bee, 310 

dew, 118 

tubes, 118 
Horn fly, 279 
Hornet, 310 
Horse bot flv, 268 

flies, 265 

louse, biting, 86 
House centipede, 17 

fly, 277, 278 
Hydrobatidae, 144 
Hydrophilidse, 174 
Hylastinus obscurus, 201, 205 
Hymenoptera, 50, 291 
Hyphantria cunea, 235 
Hypoderma bovis, 271 

lineata, 270 



Icerya purchasi, 132 
Ichneumonidse, 295 
Idiocerus alternatus, 108 
Imago, 47 

Indian meal moth, 211 
Inimical leaf hopper. 111, 112 
Insect control, 315 

powder, 321 
Insecticides, 315 
Insects, relation, 312 

structure, 38 
Internal structure of insects, 42 
iMdomyrmex humilis, 307 



INDEX 



343 



Ischnoptera, 55 

pennsylvanica, 55 
Isoptera, 49, 76 
Isosoma tritici, 301, 302 
Itch mite, 36 
Ixodidse, 30 



Jassid^, 111 
Jassoidea, 105 
June bugs, 183 



Katydid, 68 

Kerosene as an insecticide, 319 

Kissing bug, 145 



Labia minor, 71, 72 
Labium, 40 
Labrum, 40 
Lace bugs, 150 
Lachnosterna, 183 

fusca, 183, 184 
Ladybird beetles, 175 
Lampyridse, 182 
Larder beetle, 178 
Larval period, 47 

stage, 46 
Lead arsenate as an insecticide, 316 
Leaf beetles, 190 

bugs, 150 

rollers, 215 
Leafhopper terms, 106 
Lebia grandis, 173 
Legs of insects, structure, 41 
Lepidocyrtus purpureus, 53 
Lepidoptera, 50, 206 
Lepisma, 48 

domestica, 51, 53 

saccharina, 52, 54 
Leptinotarsus decemlineatus, 190 
Leptocoris trivittatus, 156, 157 
Leptus americana, 27 

irritans, 27 
Leucania unipuncta, 227 
Leucotermes flavipes, 76, 77, 81 



Libellula pulchella, 75, 76 

Lime-sulphur as an insecticide, 318 

Limnogonus hesione, 145 

Liotheidse, 84 

Locustidae, 67 

Locusts, 59 

Locust-tree borer, 210 

London purple as an insecticide, 

316 
Lucanidse, 182 
Lucanus dama, 182 
Lucilia csesar, 285 
Luna moth, 240 
Lyctidse, 178 

Lyctus planicollis, 178, 179 
Lygseidffi, 151 
Lysiphlebus, 123 

tritici, 296, 298 



M 

Machinery for the application of 

insecticides, 322 
Macrodactylus subspinosus, 184 
Macrosiphum pisi, 121, 122 
Mallophaga, 49, 83 
Mandibles of insects, 40 
Mantidse, 57 
Mantispidse, 165 
Maple scale, 133 
Margaropus annulatus, 31 
Masked bed-bug hunter, 146 
Mating of insects, 45 
Maxilla of insects, 40 
May beetles, 183 " 

fhes, 72 
Mayetiola destructor, 255, 256 
Meat fly, 286 
Mecoptera, 50, 169 
Mediterranean flour moth, 212 
MegiUa maculata, 176 
Melanoplus atlanis, 62, 65 

femur-rubrum, 61, 62 

spretus, 60 
Melanotus communis, 180 
MeUitia satyriniformis, 223 
Melophagus ovinus, 288 
Membracidse, 98 
Menopon palUdum, 84 
Mentum of insects, 40 
Metamorphosis of insects, 47 



344 



INDEX 



Micropyle, 45 

Mole cricket, 70 

Monarch butterfly, 245 

Monomera blatchleyi, 59 

Mosquitoes, 248 

Mouth structure of insects, 40 

Mullein thrips, 92 

nigra, 92 
Murgantia histrionica, 159 
Musca domestica, 277, 278 
Muscidse, 277 
Muscina stabulans, 283 
Museum beetle, 179 
MjTiopods, 17 
Myrmeleonidse, 169 



N 



Nabid^, 147 

Natural enemies of insectSj 324 

Xecrophorus, 175 

Nectaries, 118 

Nepidse, 142 

Nervous system of insects, 43 

Neuroptera, 49, 165 

Noctuidse, 226 

Notolophus leucostigma, 230 

Notonecta irrorata, 141 

undulata, 141, 142 
Notonectidse, 142 
Nut weevils, 198 
Nymphalidse, 247 



O 

Ocelli, 39 
Odonata, 49, 74 
(Ecanthus, 69 

fasciatus, 69 

niveus, 69 
(Estridae, 267 
(Estrus ovis, 275 
Oncometopia undata, 109 
Onion thrips, 90 
Onycophora, 17 
Ophion, 296 
Orange dog, 242 

white fly, 130 
Oriental cockroach, 56 
Ormenis pruinosa, 101 



Orthezia solidaginis, 131, 132 
Ortheziinae, 131 
Orthoptera, 48, 54 
Orthorapha, 248 
Otioceras, 102 
Owlet moths, 226 
Ox bot fly, 270 
Oyster-shell scale, 136 



Pachypsylla celtidis-mamma, 116 

Paleacrita vernata, 225 

Palpus, 40 

Panorpidse, 169 

PapiHo cresphontes, 242 

Papilionidae, 241 

Paraglossa, 40 

Parasita, 94, 160 

Parasitica, 295 

Parasitic insects, 324 

Paris green as insecticide, 315 

Parthenogenesis in aphids, 118 

Passalus cornutus, 182 

Pea aphis, 121, 122 

weevil, 193 
Peach-tree borer, 222 
Pear slug, 293 

thrips, 90 

-tree psylla, 115, 116 
Pedipalpi,' 23 
Pentatomidse, 159 
Periplaneta orientalis, 56 
Perla, 49 

Persian insect powder, 321 
Phalangida, 23 
Phasmidse, 58 
Phasmomantis Carolina, 57 
Philopteridae, 84 
Phlegethontius 5-maculata, 206 
Phloeothrips verbasci, 92 
Phormia terrsenova, 284 
Phorodon humuli, 119 
Phylloxera, grape, 129 
Phymatidse, 147 
Phytonomus punctatus, 195 
Pieridse, 242 
Pieris rapse, 242 
Pigeon tick, 30 
Pilophorus, 151 
Pimpla, 296 



INDEX 



345 



Pimpla conquisitor, 296, 297 
Pissodes strobi, 200 
Plant lice, 117 
Platypsyllidse, 174 
Plecoptera, 49, 72 
Plodia interpunctella, 211 
Plum curculio, 196 
Podisus maculiventris, 159 
Podura, 48 

Porthetria dispar, 232 
Praying mantis, 57 
Predaceous bugs, 145 

insects, 324 
Principles of economic entomology, 

312 
Prionoxystus robinise, 210 
Prionus, 185 
Proctotrupidae, 296, 305 
Proventriculus, 42 
Pseudococcus citri, 131 
Pseudoscorpionida, 23 
Pseudova, 118 
Psocidse, 81 
Psoroptes communis, 34 

var ovis, 35 
Psyllidge, 115 

Pteromalus puparum, 300, 301 
Pterygota, 48, 54 
Pulvinaria innumerabilis, 132, 133 
Pupa stage of insects, 47 
Pyralidge, 211 
Pyralis farinalis, 211 
Pyrethrum as an insecticide, 321 



R 



Ranatra americana, 143 
Red spider, 25 
Reduviidse, 145 
Reduvius personatus, 146 
Relation of insects, 312 
Reproduction of insects, 44 
Reproductive organs of insects, 

44 
Respiratory system of insects, 43 
Restriction as a method of insect 

control, 327 
Rhagoletis pomonella, 287, 288 
Rhyncophora, 195 
Rocky Mt. locust, 60 
Rose chafer, 184 



Rose slug, 293 
Round-headed borer. 
Rove beetles, 175 



187 



San Jose scale, 137 
Sanninoidea exitiosa, 222, 223 
Saperda Candida, 187, 189 
Sarcophagidae, 286 
I Sarcoptes scabiei, 36 
Sarcoptidae, 35 
Saw-toothed beetle, 177, 178 
Scale insects, 130 
Scaraba^idse, 182 
Schizoneura americana, 123 

lanigera, 126 
Scolytidse, 203 
Scolytus rugulosus, 202, 205 
Scorpionida, 22 
Scorpion flies, 169 
Scorpions, 22 
Screw-worm fly, 277 
Scutigera forceps, 20, 21 
Sericophanes, 151 

ocellatus, 150 
Sesiidae, 222 

Seventeen-year cicada, 95 
Sharpshooter, 109 
Sheep bot fly, 275 
i scab mite, 35 
I tick, 288 

Short-nosed ox louse, 161 
Shovel-nosed leaf hopper, 110, HI 
Sialidaj, 165 
Silk worm, 240 
Silpha, 175 
Silphidse, 175 
Silvertop, 90 
Simuliidai, 260 
Simulium pecuarum, 261 
Siphocoryne avense, 119 
Siphonaptera, 50, 289 
Six-spotted leaf hopper, 1 14 
Skippers, 241 
Smynthurus, 48 
Snowy tree cricket, 69 
Social wasps, 310 
Sod worm, 214 
Solpugida, 23 
Southern buffalo gnat, 261 



346 



INDEX 



Special senses of insects, 44 
Sphecina, 308 
(Sphecius speciosus, 310 
Spined soldier bug, 159 
Spiracles, 42 
Spotted-fever tick, 32 
Spraying codling moth, 216 
Spring grain aphis, 123 
Spring tails, 48 
Squash beetle, 191 

bug, 155 

-vine borer, 222 
Stable fly, 282 
Stag beetle, 182 
Staphylinida^, 175 
Stegomyia fasciata, 252 
Sternorhynchi, 94, 115 
Stink bugs, 159 
Stomoxys calcitrans, 282 
Stone crickets, 68 

flies, 72 
Structure of insects, 38 
Submentum, 40 
Sugar-cane hopper, 103 
Swallowtail butterflies, 241 
Sword bearers, 67 
Sylvanus surinamensis, 177 
Syrphidae, 266 



TABANID.E, 265 

Tabanus atratus, 266 
Tachinidse, 275 
Tarnished plant bug, 150 
Tenderfoot leaf hopper, 109 
Tent caterpillar, 235 
Tenthredinidai, 292 
Terebrantia, 88 
Termites, 76 
Termitidae, 76 
Tetranychus bimaculatus, 25 

gloveri, 26 
Tettigoniellida, 108 
Thalessa, 296 

atrata, 295 

lunator, 295 
Thorax structure of insects, 41 
Thread-legged bug, 147 
Thripida?, 88 
Thrips tabaci, 90 



Thrips tritici, 89 

Thyridopteryx ephemera^formis, 

207, 209 
Thysanoptera, 49, 87 
Thysanura, 48, 52 
Tibicen septendecim, 94, 95 
Tick, cattle, 31 

spotted fever, 31 
Ticks, 30 
Tiger beetles, 173 
Tinea pellionella, 221 
Tineidai, 221 
Tineola biselliella, 222 
Tingitidse, 150 
Tobacco extract, 320 
Tomato- worm larva, 206 
Tortricida?, 215 

Toxoptera graminum, 122, 123 
Trachea of insects, 43 
Transformations of insects, 45 
Tree crickets, 69 

-hoppers, 98 
Tremex columba, 294 
Trichodectes, 84 

parumpilosus, 86 

scalaris, 85 
Trichoptera, 50, 170 
Trimerotropis maritima, 64, 65 
Trombidiida?, 26 
Tsetse flies, 283 
Tussock moths, 230 
Typhlocyba comes, 114 
Typhlocybidae, 114 



Unity of habit of insect groups, 314 
Uroceridse, 293 



Vedalia, 177 
cardinalis, 132 

Vespa germanica, 310 
maculata, 310 

Vespidae, 310 

Viceroy butterfly, 247 



INDEX 



347 



W 

Walking-stick, 58 
Wasps, 308 
Water beetles, 174 

boatmen, 141 

bugs, 142 

scorpions, 142 

striders, 144 
Web-worm moths, 234 
Wheel bug, 146 
Whip scorpion, 23 
Whirligig beetles, 174 
White ants, 76 

fly, 130 

-marked tussock moth, 230 

pine weevil, 200, 203 



Willow saw fly, 292 

scale, 135 
Wings, structure of insects', 41 
Wire worm, 180 
Wood borers, 185 
Woolly aphis, 126 



Yellow-fever mosquito, 252 
Yellow jacket, 310 



Zaitha fluminea, 141 



